GC-MS Analysis: In Vivo Hepatoprotective and Antioxidant Activities of the Essential Oil of Achillea biebersteinii Afan. Growing in Saudi Arabia.

Liver disease is a worldwide problem. It represents one of the main causes of morbidity and mortality in humans. Achillea biebersteinii is used as herbal remedy for various ailments including liver diseases. But the scientific basis for its medicinal use remains unknown. Thus, this research was undertaken to evaluate the efficiency of A. biebersteinii essential oil (ABEO) (0.2 mL/kg) in the amelioration of CCl4-induced hepatotoxicity in rodent model. Moreover, the chemical content of the oil was investigated using GC and GC-MS. The following biochemical parameters were evaluated: serum glutamic oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), gamma-glutamyl-transpeptidase (γ-GGT), alkaline phosphatase (ALP), and total bilirubin. Furthermore, lipid profile, malondialdehyde (MDA), nonprotein sulfhydryl (NP-SH), and total protein (TP) contents in liver tissue were estimated. 44 components (92.0%) of the total oil have been identified by GC-MS analysis where α-terpinene and p-cymene were the most abundant. The high serum enzymatic (GOT, GPT, GGT, and ALP) and bilirubin concentrations as well as the level of MDA, NP-SH, and TP contents in liver tissues were significantly reinstated towards normalization by the ABEO. Histopathological study further confirmed these findings. In addition, ABEO showed mild antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ß-carotene-linoleic acid assays.

Assessment of antinociceptive, antipyretic and antimicrobial activity of Piper cubeba L. essential oil in animal models.

This study was designed to investigate the possible antiniciceptive, antipyretic and antimicrobial activities of the essential oil obtained from the fruits of Piper Cubeba (L.). To assess the antinociceptive and antipyretic activities, three doses (150, 300 and 600 mg/kg, i.p.) were tested in acetic acid-induced abdominal writhing, tail flick reaction and hot-plate and Brewer's yeast-induced hyperpyrexia test models in animals. Moreover, the antimicrobial activity was examined using agar diffusion method and broth micro-dilution assay for minimum inhibitory concentrations (MIC). The Piper Cubeba essential oil (PCEO) showed a marked antinociception (17, 30 and 54%) and an increase in reaction time in mice in the flick tailed and hot-plate tests. The brewer's yeast induced hyperpyrexia was decreased in a dose dependent manner. PCEO also exhibited a strong antimicrobial potential. These findings confirm the traditional analgesic indications of P. cubeba oil and provide persuasive evidence and support its use in Arab traditional medicine.

'Ajwa' dates (Phoenix dactylifera L.) extract ameliorates isoproterenol-induced cardiomyopathy through downregulation of oxidative, inflammatory and apoptotic molecules in rodent model.

BACKGROUND/PURPOSE: Ajwa, a special variety of Saudi Arabian dates (Phoenix dactylifera L.) is a rich source of nutrients, fibers and bioactive molecules. While previous studies have shown the therapeutic value of dates phytoconstituents in liver and kidney diseases etc., its cardioprotective potential remains elusive. We therefore, investigated the cardioprotective effect of lyophilized Ajwa extract (AJLE) ex vivo as well as in vivo. METHODS: Ex vivo cardioprotective effect of AJLE was evaluated on DCFH-toxicated cardiomyoblast cells (H9C2). In vivo hemodynamics, cardiac function, serum cardiac enzymes, myocardial antioxidant, inflammatory and apoptotic biomarkers as well as histopathological parameters were studied in IPS-injured Wistar rat heart tissues. RESULTS: AJLE (250 µg/ml) attenuated the cytotoxicity and enhanced the H9C2 proliferation by up to 40%. Oral administration of AJLE (250 and 500 mg/kg.bw) prevented the depletion of endogenous antioxidants (CAT, SOD, NP-SH and NO) and myocyte injury marker enzymes, and inhibited lipid peroxidation (MDA, MPO). Moreover, AJLE downregulated the expressions of proinflammatory cytokines (IL-6, IL-10 and TNFα) and apoptotic markers (caspase-3 and Bax), and upregulated the anti-apototic protein Bcl2. Histological data showed that AJLE pretreatment reduced myonecrosis, edema, and infiltration of inflammatory cells and restored the cardiomyocytes architecture. CONCLUSION: Taken together, our data revealed that AJLE had strong antioxidant, hypolipidimic, cardioprotective, anti-inflammatory and anti-apoptotic potential against myocardial damage. This further endorses the use of Ajwa in Arabian traditional medicine against cardiovascular diseases.

Evaluation of the effectiveness of Piper cubeba extract in the amelioration of CCl4-induced liver injuries and oxidative damage in the rodent model.

Background. Liver diseases still represent a major health burden worldwide. Moreover, medicinal plants have gained popularity in the treatment of several diseases including liver. Thus, the present study was to evaluate the effectiveness of Piper cubeba fruits in the amelioration of CCl4-induced liver injuries and oxidative damage in the rodent model. Methods. Hepatoprotective activity was assessed using various biochemical parameters like SGOT, SGPT, γ-GGT, ALP, total bilirubin, LDH, and total protein. Meanwhile, in vivo antioxidant activities as LPO, NP-SH, and CAT were measured in rat liver as well as mRNA expression of cytokines such as TNFα, IL-6, and IL-10 and stress related genes iNOS and HO-1 were determined by RT-PCR. The extent of liver damage was also analyzed through histopathological observations. Results. Treatment with PCEE significantly and dose dependently prevented drug induced increase in serum levels of hepatic enzymes. Furthermore, PCEE significantly reduced the lipid peroxidation in the liver tissue and restored activities of defense antioxidant enzymes NP-SH and CAT towards normal levels. The administration of PCEE significantly downregulated the CCl4-induced proinflammatory cytokines TNFα and IL-6 mRNA expression in dose dependent manner, while it upregulated the IL-10 and induced hepatoprotective effect by downregulating mRNA expression of iNOS and HO-1 gene.

Beetroot (Beta vulgaris L.) extract ameliorates gentamicin-induced nephrotoxicity associated oxidative stress, inflammation, and apoptosis in rodent model.

The present investigation was designed to investigate the protective effect of (Beta vulgaris L.) beat root ethanolic extract (BVEE) on gentamicin-induced nephrotoxicity and to elucidate the potential mechanism. Serum specific kidney function parameters (urea, uric acid, total protein, creatinine, and histopathology of kidney tissue) were evaluated to access gentamicin-induced nephrotoxicity. The oxidative/nitrosative stress (Lipid peroxidation, MDA, NP-SH, Catalase, and nitric oxide levels) was assessed. The inflammatory response (TNF-α, IL-6, MPO, NF-κB (p65), and NF-κB (p65) DNA binding) and apoptotic marker (Caspase-3, Bax, and Bcl-2) were also evaluated. BVEE (250 and 500 mg/kg) treatment along with gentamicin restored/increased the renal endogenous antioxidant status. Gentamicin-induced increased renal inflammatory cytokines (TNF-α and IL-6), nuclear protein expression of NF-κB (p65), NF-κB-DNA binding activity, myeloperoxidase (MPO) activity, and nitric oxide level were significantly down regulated upon BVEE treatment. In addition, BVEE treatment significantly reduced the amount of cleaved caspase 3 and Bax, protein expression and increased the Bcl-2 protein expression. BVEE treatment also ameliorated the extent of histologic injury and reduced inflammatory infiltration in renal tubules. These findings suggest that BVEE treatment attenuates renal dysfunction and structural damage through the reduction of oxidative stress, inflammation, and apoptosis in the kidney.

GC and GC/MS analysis of essential oil composition of the endemic Soqotraen Leucas virgata Balf.f. and its antimicrobial and antioxidant activities.

Leucas virgata Balf.f. (Lamiaceae) was collected from the Island Soqotra (Yemen) and its essential oil was obtained by hydrodistillation. The chemical composition of the oil was investigated by GC and GC-MS. Moreover, the essential oil was evaluated for its antimicrobial activity against two Gram-positive bacteria, two Gram-negative bacteria, and one yeast species by using broth micro-dilution assay for minimum inhibitory concentrations (MIC) and antioxidant activity by measuring the scavenging activity of the DPPH radical. The investigation led to the identification of 43 constituents, representing 93.9% of the total oil. The essential oil of L. virgata was characterized by a high content of oxygenated monoterpenes (50.8%). Camphor (20.5%) exo-fenchol (3.4%), fenchon (5.4%), and borneol (3.1%) were identified as the main components. Oxygenated sesquiterpenes were found as the second major group of compounds (21.0%). ß-Eudesmol (6.1%) and caryophyllene oxide (5.1%) were the major compounds among oxygenated sesquiterpenes. The results of the antimicrobial assay showed that the oil exhibited a great antibacterial activity against the tested S. aureus, B. subtilis, and E. coli. No activity was found against P. aeruginosa and C. albicans. Moreover, the DPPH-radical scavenging assay exhibited only a moderate antioxidant activity (31%) for the oil at the highest concentration tested (1 mg/mL).

Citrus medica "Otroj": attenuates oxidative stress and cardiac dysrhythmia in isoproterenol-induced cardiomyopathy in rats.

Citrus medica L. commonly known as Otroj, is an important medicinal plant reputed for its nutritious and therapeutic uses. The present work was undertaken to investigate the protective effect of the ethanolic extract of otroj (EEOT) against isoproterenol (ISO)-induced cardiotoxicity in rats. In addition, the antioxidant activity and the phenolic and flavonoidal contents were determined. Rats were administered EETO (250 and 500 mg/kg) or vehicle orally for 15 days along with ISO (85 mg/kg, s.c.) on the 14th and 15th day. ISO induced cardiac dysfunction, increased lipid peroxidation and alteration of myocyte-injury specific marker enzymes. ISO also showed an increase in levels of plasma cholesterol, triglycerides (TG), LDL-C, and VLDL-C. Moreover, the histological investigations showed myocardial necrosis and inflammation. EETO treatment brought the above parameters towards normal level. Moreover, in vitro DPPH radical scavenging and ß-carotene-linoleic acid tests of the EEOT exhibited a notable antioxidant activity in both assays used. In addition, histopathological examination reconfirmed the protective effects of EEOT. Thus, the present study reveals that C. medica alleviates myocardial damage in ISO-induced cardiac injury and demonstrates cardioprotective potential which could be attributed to its potent antioxidant and free radical scavenging activity.

Phoenix dactylifera L. spathe essential oil: chemical composition and repellent activity against the yellow fever mosquito.

Date palm, Phoenix dactylifera L. (Arecaceae), grows commonly in the Arabian Peninsula and is traditionally used to treat various diseases. The aim of the present study was to identify chemical composition of the essential oil and to investigate the repellent activity. The essential oil of P. dactylifera was obtained by hydrodistillation from the spathe, a specialized leaf structure that surrounds the pollinating organs of the palm. The oil was subsequently analyzed by GC-FID and GC-MS. The oil showed promising repellent activity against yellow fever mosquito - Aedes aegypti. Sixteen components were characterized, constituting 99% of the oil. The main components were 3,4-dimethoxytoluene (73.5%), 2,4-dimethoxytoluene (9.5%), ß-caryophyllene (5.5%), p-cresyl methyl ether (3.8%), and caryophyllene oxide (2.4%). The minimum effective dosage (MED) for repellency for the P. dactylifera oil was 0.051mg/cm(2), which had moderately lower potency compared to reference standard N,N-diethyl-3-methylbenzamide, DEET (0.018mg/cm(2)) in the "cloth patch assay". The five major compounds were individually assayed for repellency to determine to what extent each is responsible for repellency from the oil. 3,4-Dimethoxytoluene and 2,4-dimethoxytoluene showed the best repellent activity with the same MED value of 0.063mg/cm(2), respectively. The results indicate that these two constituents which comprise a large proportion of the P. dactylifera oil (83%) are likely responsible for the observed repellent activity. In this aspect, the P. dactylifera spathe oil is a sustainable, promising new source of natural repellents.

Attenuation of CCl4-Induced Oxidative Stress and Hepatonephrotoxicity by Saudi Sidr Honey in Rats.

The present study was undertaken to investigate the possible protective effect of Saudi Sidr honey (SSH) on carbon tetrachloride (CCl4) induced oxidative stress and liver and kidney damage in rat. Moreover, the antioxidant activity and the phenolic and flavonoidal contents were determined. The hepatorenal protective activity of the SSH was determined by assessing biochemical, hematological, and histological parameters. Serum transaminases, ALP, GGT, creatinine, bilirubin urea, uric acid, and MDA level in liver and kidney tissues were significantly elevated, and the antioxidant status of nonprotein sulfhydryls, albumin, and total protein levels in liver and kidney were declined significantly in CCl4 alone treated animals. Pretreatment with SSH and silymarin prior to the administration of CCl4 significantly prevented the increase of the serum levels of enzyme markers and reduced oxidative stress. SSH also exhibited a significant lipid-lowering effect and caused an HDL-C enhanced level in serum. The histopathological evaluation of the liver and kidney also revealed that honey protected incidence of both liver and kidney lesions. Moreover, SSH showed a strong antioxidant activity in DPPH and ß -carotene-linoleic acid assays. SSH was found to contain phenolic compounds. Additionally, the SSH supplementation restored the hepatocytes viability against 2',7'-dichlorofluorescein (DCF) toxicity in ex vivo test.

Biotransformation of vulgarin.

Using a standard two-stage fermentation technique, the fungus Beauveria bassiana (ATCC 7159) was found to convert the eudesmanolide vulgarin (1) to 1α,4α-dihydroxy-5αH,6,11ßH-eudesman-6,12-olide (2). The use of the yeastHansenula anomala ATCC 20170 instead, produced the less polar 4α-hydroxy-1-oxo-5αH,6,11ßH-eudesman-6,12-olide(3), in addition to the more polar 3α,4α-dihydroxy-1-oxo-5αH,6,11ßH-eudesman-6,12-olide (4). These metabolites were characterized on the basis of their spectral data and the identity of 4 was further confirmed by chemical synthesis.

Edible oils for liver protection: hepatoprotective potentiality of Moringa oleifera seed oil against chemical-induced hepatitis in rats.

In the present study, in vitro antioxidant, antioxidative stress and hepatoprotective activity of Moringa oleifera Lam. seed oil (Ben oil; BO) was evaluated against carbon tetrachloride (CCl(4) ) induced lipid peroxidation and hepatic damage in rats. The oil at 0.2 and 0.4 mL/rat was administered orally for 21 consecutive days. The substantially elevated serum enzymatic (GOT, GPT, ALP, GGT) and bilirubin levels were significantly restored towards normalization by the oil. There was a significant elevation in the level of malondialdehyde (MDA), non-protein sulfhydryl (NP-SH), and total protein (TP) contents in the liver tissue. The results obtained indicated that BO possesses potent hepatoprotective action against CCl(4) -induced hepatic damage by lowering liver marker enzymes, MDA concentration, and elevating NP-SH and TP levels in liver tissue. The biochemical observations were supplemented with histopathological examination of rat liver. The results of this study showed that treatment with Ben oil or silymarin (as a reference) appears to enhance the recovery from hepatic damage induced by CCl(4) . The pentobarbital induced narcolepsy prolongation in mice was retarded by the Ben oil. Acute toxicity test in mice showed no morbidity or mortality. In vitro DPPH radical scavenging and ß-carotene-linolic acid assay tests of the BO exhibited a moderate antioxidant activity in both tests used. The possible mechanism(s) of the liver protective activity of Ben oil activity may be due to free radical scavenging potential caused by the presence of antioxidant component(s) in the oil. Consequently, BO can be used as a therapeutic regime in treatment of some hepatic disorders.

Convergent evolution of a complex fruit structure in the tribe Brassiceae (Brassicaceae).

PREMISE OF STUDY: Many angiosperms have fruit morphologies that result in seeds from the same plant having different dispersal capabilities. A prime example is found in the Brassiceae (Brassicaceae), which has many members with segmented or heteroarthrocarpic fruits. Since only 40% of the genera are heteroarthrocarpic, this tribe provides an opportunity to study the evolution of an ecologically significant novelty and its variants. METHODS: We analyzed nuclear (PHYA) and plastid (matK) sequences from 66 accessions using maximum parsimony, maximum likelihood, and Bayesian inference approaches. The evolution of heteroarthrocarpy and its variants was evaluated using maximum parsimony and maximum likelihood ancestral state reconstructions. KEY RESULTS: Although nuclear and plastid phylogenies are incongruent with each other, the following findings are consistent: (1) Cakile, Crambe, Vella, and Zilla lineages are monophyletic; (2) the Nigra lineage is not monophyletic; and (3) within the Cakile clade, Cakile, Didesmus, and Erucaria are paraphyletic. Despite differences in the matK and PHYA topologies at both deep and shallow nodes, similar patterns of morphological evolution emerge. Heteroarthrocarpy, a complex morphological trait, has evolved multiple times across the tribe. Moreover, there are convergent transitions in dehiscence capabilities and fruit disarticulation across the tribe. CONCLUSIONS: We present the first explicit analysis of fruit evolution within the Brassiceae, which exemplifies evolutionary lability. The repeated loss and gain of segment dehiscence and disarticulation suggests conservation in the genetic pathway controlling abscission with differential expression across taxa. This study provides a strong foundation for future studies of mechanisms underlying variation in dispersal capabilities of Brassiceae.

Gastric antiulcer, antisecretory and cytoprotective properties of celery (Apium graveolens) in rats.

In the present investigation, an ethanol extract of celery [Apium graveolens L. (Apiaceae/Umbelliferae)], at doses of 250 and 500 mg/kg body weight, was evaluated for antigastric ulcer activity using various experimental gastric ulcer models in rats. Ulcers were induced by indomethacin, cytodestructive agents (80% ethanol, 0.2 M NaOH and 25% NaCl) and cold restraint stress. Gastric secretory studies were undertaken by using pylorus ligation (Shay rat model). In addition to gastric wall mucus (GWM), non-protein sulfhydryl (NP-SH) and malondialdehyde (MDA) were also estimated in gastric tissues after 80% ethanol treatment. Pretreatment of celery extract produced dose-dependent reduction in all experimentally induced gastric lesions. Ethanol (80%) decreased the levels of GWM, NP-SH and increase in MDA concentration in gastric tissue. Celery extract showed the ability to significantly replenish the ethanol-induced depleted levels of GWM and gastric mucosal NP-SH. The gastric mucosal MDA level was also significantly lowered in extract pretreated rats. The celery extract showed stomach protection against the models used for ulcerogenesis. Results were further confirmed by using histopathological assessment. The phytochemical screening showed the presence of various chemical constituents such as flavonoids, tannins, volatile oils, alkaloids, sterols and/or triterpenes. Acute toxicity test revealed no deleterious or toxic symptoms or mortality over a period of 14 days. However, the LD(50) was found to be 7.55 g/kg, and showed a large margin of safety. The results suggest that Apium graveolens extract significantly protects the gastric mucosa and suppresses the basal gastric secretion in rats, possibly through its antioxidant potential.

Protective Effect of Origanum majorana L. 'Marjoram' on various models of gastric mucosal injury in rats.

'Marjoram,' Origanum majorana L., a culinary aromatic medicinal herb is known to possess various therapeutic properties. We evaluated the antiulcerogenic activity of the ethanol extract in hypothermic restraint stress-, indomethacin-, necrotizing agents- (80% ethanol, 25% NaCl and 0.2 M NaOH) induced ulcers and basal gastric acid secretion using pylorus ligated Shay rat-model. Marjoram at doses of 250 and 500 mg/kg of body weight, significantly decreased the incidence of ulcers, basal gastric secretion and acid output. Furthermore, the extract replenished the ethanol-induced depleted gastric wall mucus and nonprotein sulfhydryls (NP-SH) contents and significantly lowered the increase in the concentration of malondialdehyde (MDA). Ulcer preventing potential was further confirmed by histopathological assessment. An acute toxicity test showed a large margin of safety of the extract in mice. The phytochemical screening of aerial parts of marjoram revealed the presence of volatile oil, flavonoids, tannins, sterols and/or triterpenes.

Rocket "Eruca sativa": a salad herb with potential gastric anti-ulcer activity.

AIM: To validate gastric anti-ulcer properties of Rocket "Eruca sativa" on experimentally-induced gastric secretion and ulceration in albino rats. METHODS: Gastric acid secretion studies were undertaken using pylorus-ligated rats. Gastric lesions in the rats were induced by noxious chemicals including ethanol, strong alkalis, indomethacin and hypothermic restraint stress. The levels of gastric wall mucus (GWM), nonprotein sulfhydryls (NP-SH) and malondialdehyde (MDA) were also measured in the glandular stomach of rats following ethanol administration. The gastric tissue was also examined histologically. The extract was used in two doses (250 and 500 mg/kg body weight) in all experiments. RESULTS: In pylorus-ligated Shay rats, the ethanolic extract of Rocket "Eruca sativa L." (EER) significantly and dose-dependently reduced the basal gastric acid secretion, titratable acidity and ruminal ulceration. Rocket extract significantly attenuated gastric ulceration induced by necrotizing agents (80% ethanol, 0.2 mol/L NaOH, 25% NaCl), indomethacin and hypothermic restraint stress. The anti-ulcer effect was further confirmed histologically. On the other hand, the extract significantly replenished GWM and NP-SH levels, as well as the MDA level significantly reduced by extract pretreatment. CONCLUSION: Rocket extract possesses anti-secretory, cytoprotective, and anti-ulcer activities against experimentally-induced gastric lesions. The anti-ulcer effect is possibly through prostaglandin-mediated activity and/or through its anti-secretory and antioxidant properties.

Gastroprotective effect of an aqueous suspension of black cumin Nigella sativa on necrotizing agents-induced gastric injury in experimental animals.

BACKGROUND/AIM: Previous studies on "Black seed" or "Black Cumin" Nigella sativa (NS) have reported a large number of pharmacological activities including its anti-ulcer potential. These studies employed either fixed oil, volatile oil components or different solvent extracts. In folkloric practices, NS seeds are taken as such, in the form of coarse dry powder or the powdered seeds are mixed with water. This study examines the effect of NS aqueous suspension on experimentally induced gastric ulcers and basal gastric secretion in rats to rationalize its use by herbal and Unani medicine practitioners. MATERIALS AND METHODS: The study was conducted at the Medicinal, Aromatic and Poisonous Plants Research Center, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia. Acute gastric ulceration was produced by various noxious chemicals (80% ethanol, 0.2 M NaOH, 25% NaCl and indomethacin) in Wistar albino rats. Anti-secretory studies were undertaken in a separate group of rats. Gastric wall mucus contents and non-protein sulfhydryl concentration were estimated, and gastric tissue was examined histopathologically. RESULTS: An aqueous suspension of Black seed significantly prevented gastric ulcer formation induced by necrotizing agents. It also significantly ameliorated the ulcer severity and basal gastric acid secretion in pylorus-ligated Shay rats. Moreover, the suspension significantly replenished the ethanol-induced depleted gastric wall mucus content levels and gastric mucosal non-protein sulfhydryl concentration. The anti-ulcer effect was further confirmed histopathologically. CONCLUSION: These findings validate the use of Black seed in gastropathies induced by necrotizing agents. The anti-ulcer effect of NS is possibly prostaglandin-mediated and/or through its antioxidant and anti-secretory activities.

Effect of Commiphora opobalsamum (L.) Engl. (Balessan) on experimental gastric ulcers and secretion in rats.

The ulcer protective potential of an ethanol extract of Commiphora opobalsamum (L.) Engl. (Burseraceae) 'Balessan' was assessed against different acute gastric ulcer models in rats induced by necrotizing agents (80% ethanol, 0.2M NaOH and 25% NaCl), hypothermic restraint stress, pyloric ligation (Shay) and indomethacin. Balessan, 250 and 500 mg/kg administered orally (intraperitoneally in Shay rat model) showed a dose-dependent ulcer protective effects in all the above ulcer models. Besides, the extract offered protection against ethanol-induced depletion of stomach wall mucus and reduction in nonprotein sulfhydryl (NP-SH) concentration. Ethanol treatment also caused histopathological lesions of the stomach wall. Pretreatment with Balessan extract provided a complete protection of gastric mucosa through supporting both the offensive and defensive factors. Balessan extract was also showed a large margin of safety without any apparent adverse effects in rats.

Medicinal plant diversity in the flora of Saudi Arabia 1: a report on seven plant families.

A preliminary survey on the medicinal plant diversity in the flora of the Kingdom of Saudi Arabia has been made with seven families: Amaranthaceae, Apocynaceae, Capparidaceae, Euphorbiaceae, Labiatae, Polygonaceae and Solanaceae, as an initial study. These families are represented in the flora with 254 species (i.e. 12% of the total species), and individually with 21, 7, 29, 66, 76, 22 and 33 species, respectively. Of these, 86 species, so far investigated, are medicinal, distributed in these seven families as follows: 7, 5, 12, 20, 23, 7 and 12, respectively. The Labiatae have the highest number (23) of medicinal plants among them while maximum medicinal plant diversity within the family has been observed with the Apocynaceae. An enumeration of these 86 medicinal species is presented with the current nomenclature, Arabic names and medicinal uses. This communication aims at emphasizing the importance of setting up conservation priorities, and sustained development of various medicinal plants of Saudi Arabia.

New oxypregnane glycosides from Caralluma penicillata.

The ether fraction of the defatted ethanol extract of the aerial parts of Caralluma penicillata (defl) M. E. Br. (Asclepiadaceae) yielded four new oxypregnane glycosides, penicillosides D-G. The structures of the isolated compounds were established by different spectroscopic methods.

neo-Clerodane diterpenoids from Teucrium oliverianum and structure revision of teucrolin E.

The aerial parts of Teucrium oliverianum yielded two neo-clerodane diterpenoids, teucrolin F and G, together with the known teucrolin E. The previously proposed structure for teucrolin E was revised so that it contains a tetrahydrofuran ring instead of an oxetane ring. This was based on analysis of the NMR spectroscopic data of its diacetate, including its NOE spectra. In addition, the structural assignments of the new diterpenoids were based on 1H and 13C NMR spectroscopic studies, mainly 2D NMR experiments, including homonuclear and heteronuclear correlations.