Protection of gastric mucosal damage by Coriandrum sativum L. pretreatment in Wistar albino rats.

The effect of Coriander pretreatment on gastric mucosal injuries caused by NaCl, NaOH, ethanol, indomethacin and pylorus ligation accumulated gastric acid secretions was investigated in rats. Pretreatment at oral doses of 250 and 500mg/kg, body weight was found to provide a dose-dependent protection against the (i) ulcerogenic effects of different necrotizing agents; (ii) ethanol-induced histopathological lesions; (iii) pylorus ligated accumulation of gastric acid secretions and ethanol related decrease of Nonprotein Sulfhydryl groups (NP-SH). Results obtained on the study of gastric mucus and indomethacin-induced ulcers demonstrated that the gastro protective activity of Coriander might not be mediated by gastric mucus and/or endogenous stimulation of prostaglandins. The protective effect against ethanol-induced damage of the gastric tissue might be related to the free-radical scavenging property of different antioxidant constituents (linanool, flavonoids, coumarins, catechins, terpenes and polyphenolic compounds) present in Coriander. The inhibition of ulcers might be due to the formation of a protective layer of either one or more than one of these compounds by hydrophobic interactions.

Dihydroagarofuran alkaloid and triterpenes from Maytenus heterophylla and Maytenus arbutifolia.

The antimicrobially active EtOH extracts of Maytenus heterophylla yielded a new dihydroagarofuran alkaloid,1beta-acetoxy-9alpha-benzoyloxy-2beta,6alpha-dinicotinoyloxy-beta-dihydroagarofuran, together with the known compounds beta-amyrin, maytenfolic acid, 3alpha-hydroxy-2-oxofriedelane-20alpha-carboxylic acid, lup-20(29)-ene-1beta,3beta-diol, (-)-4'-methylepigallocatechin, and (-)-epicatechin. In addition, beta-amyrin, (-)-epicatechin and (-)-4'-methylepigallocatechin were isolated from Maytenus arbutifolia. The structure elucidation of the isolated compounds was based primarily on 1D and 2D NMR analyses, including HMQC, HMBC, and NOESY correlations. Maytenfolic acid showed moderate antimicrobial activity by inhibiting the growth of Candida albicans, Cryptococcus neoformans, Staphylococcus aureus and Pseudomonas aeruginosa.

A weakly antimalarial biflavanone from Rhus retinorrhoea.

The biflavanone (2S,2"S)-7,7"-di-O-methyltetrahydroamentoflavone and five known flavonoids, 7-O-methylnaringenin, 7,3'-O-dimethylquercetin, 7-O-methylapigenin, 7-O-methylluteolin, and eriodictyol were isolated from the leaves of Rhus retinorrhoea Steud, Ex Olive. The biflavanone exhibited moderate antimalarial activity with IC50 0.98 microg/ml against Plasmodium falciparum (W2 Clone) and weak activity against P. falciparum (D6 Clone) with IC50 2.8 microg/ml. Nevertheless, it did not display any cytotoxicity. 7-O-Methylnaringenin showed weak antimicrobial activity against Candida albicans, C. krusei, Staphylococcus aureus, Mycobacterium smegmatis, M. intracellulare, and M. xenopi with MIC approximately 100 microg/ml. Characterization of each compound was based on spectral analysis and comparison with reported data.

Labdane diterpenes from Otostegia fruticosa.

The new labdane diterpenes otostegin A (2), otostegin B (6) and 15-epi-otostegin B (7) were isolated from the aerial parts of Otostegia. fruticosa, besides the previously known labdanes preleoheterin (1), leoheterin (3), leopersin C and 15-epi-leopersin C (4, 5), ballonigrin (9) and vulgarol (11), along with the iridoid glucoside 8-O-acetylharpagide (10). The structure elucidation of all the isolated compounds was based on their spectral data and chemical derivatization.

Bioactive 12-oleanene triterpene and secotriterpene acids from Maytenus undata.

The aerial parts of Maytenus undata yielded four new 12-oleanene and 3,4-seco-12-oleanene triterpene acids, namely, 3-oxo-11alpha-methoxyolean-12-ene-30-oic acid (1), 3-oxo-11alpha-hydroxyolean-12-ene-30-oic acid (2), 3-oxo-olean-9(11), 12-diene-30-oic acid (3), and 3,4-seco-olean-4(23),12-diene-3, 29-dioic acid (20-epi-koetjapic acid) (5), together with the known 3, 11-dioxoolean-12-ene-30-oic acid (3-oxo-18beta-glycyrrhetinic acid) (4), koetjapic acid (6), and the 12-oleanene artifact 3-oxo-11alpha-ethoxyolean-12-ene-30-oic acid (7). Koetjapic acid (6) inhibited the growth of Staphylococcus aureus, methicillin-resistant S. aureus, and Pseudomonas aeruginosa, with an MIC range of 3.125-6.25 microg/mL. The new 3,4-secotriterpene acid 20-epi-koetjapic acid (5) potently inhibited rat neonatal brain microglia phorbol ester-stimulated thromboxane B(2) (IC(50) = 0.5 microM) and superoxide anion (IC(50) = 1.9 microM) generation.

Hirsutinolides from Vernonia cinerascens.

The aerial parts of Vernonia cinerascens, collected in Saudi Arabia, yielded a new hirsutinolide, together with three known lactones. The structure of the new compound was elucidated using, 1H NMR, 13C NMR, 1H-1H COSY, 1H-13C HETCOR and HMBC.

New eudesmane sesquiterpenes from Plectranthus cylindraceus.

Three new eudesmane sesquiterpenes, plectranthone (1), desacetylplectranthone (2), isodeacetylplectranthone (3), and the three known flavonols pachypodol, casticin, and chrysosplenol D were isolated for the first time from the aerial parts of Plectranthus cylindraceus. Their structures have been established on the basis of spectral data. The structures and relative stereochemistries of 1 and 2 were confirmed by single-crystal X-ray analysis.

Cell culture assay system for the evaluation of natural product-mediated anti-Hepatitis B virus activity.

Utilizing the hepatitis B virus (HBV)-producing hepatoblastoma cell line, HepG2.2.15, which is stably transfected with the cloned HBV genome, methods were devised to examine the effects of test substances on intracellular extrachromosomal HBV DNA levels and secretion of hepatitis B surface antigen (HBsAg). The known inhibitor of HBV replication, dideoxycytosine (ddC), had a minor effect on the secretion of HBsAg, but >90% of intracellular extrachromosomal HBV DNA expression was lost at a non-cytotoxic drug concentration (25µM). This inhibitory effect was reversed when ddC was removed from the medium. Of 19 plant materials tested, extracts from the aerial parts of Clematis sinensis Lour, and Clerodendron inerme R. Br. significantly inhibited the secretion of HBsAg into the culture medium at non-cytotoxic concentrations, but had no effect on intracellular extrachromosomal HBV DNA levels. This system is useful for the evaluation of test materials, or combinations of test materials, for their potential to inhibit HBV markers.

Glucose-conjugation of the flavones of Psiadia arabica by Cunninghamella elegans.

Microbial transformation of psiadiarabin and its 6-desmethoxy analogue 5,3' dihydroxy-7,2',4'5'-tetramethoxyflavone by Cunninghamella elegans NRRL 1392 gave the 3'-glucoside conjugates of the two flavones. Structural elucidation of these two new metabolites was achieved using 1D and 2D NMR spectroscopy and CIMS.

Pharmacological and safety evaluation studies on Lepidium sativum L., Seeds.

An ethanolic extract of Cress (Lepidium sativum L.) seeds has been studied for anti-inflammatory, antipyretic and analgesic activities and to evaluate the safety of their acute and chronic use in rodents. The extract significantly inhibited carrageenan-induced paw edema and reduced the yeast-induced hyperpyrexia. It also prolonged the reaction time of mice on the hot plate. However, the extract exacerbated indomethacin-induced gastric mucosal damage. The coagulation studies showed a significant increase in fibrinogen level and an insignificant decrease in prothrombin time, confirming its coagulating property. The toxicity tests showed that the administration of extract in single doses of 0.5 to 3.0g/kg did not produce any adverse effects or mortality in mice, whereas the animals treated with extract (100 mg/kg/day) for a period of 3 months in drinking water showed no symptoms of toxicity except a statistically insignificant higher mortality rate. These findings suggest that the seeds of Cress (L. sativum) possess significant anti-inflammatory, antipyretic, analgesic and coagulant activities, and are free from serious side or toxic effects.

Protective effect of Swertia chirata against indomethacin and other ulcerogenic agent-induced gastric ulcers.

The effect of Swertia chirata has been studied on experimentally induced gastric ulcers in rats. The ethanolic extract of chirata significantly reduced the intensity of gastric mucosal damage induced by indomethacin and necrotizing agents. It produced a significant decrease in gastric secretion in pylorus-ligated rats. The extract inhibited acetylcholine-induced contraction of guinea pig ileum, suggesting its anti-cholinergic activity. Pretreatment of rats with the extract significantly prevented ethanol-induced gastric wall mucus depletion and restored the non-protein sulfhydryl (NP-SH) content in the glandular stomachs. These findings support the use of chirata for the treatment of gastric ulcers in traditional medicine.

Isolation and characterization of two antimicrobial agents from mace (Myristica fragrans).

The two antimicrobial resorcinols malabaricone B [1] and malabaricone C [2] were isolated from mace, the dried seed covers of Myristica fragrans. Both compounds exhibited strong antifungal and antibacterial activities. Structure modifications by methylation or reduction resulted in diminished activity.

Pharmacological studies on aerial parts of Calotropis procera.

The decoction of the aerial part of Calotropis procera is commonly used in Saudi Arabian traditional medicine for the treatment of variety of diseases including fever, joint pain, muscular spasm and constipation. The present investigation was undertaken to confirm its claimed activity in traditional medicine. The ethanol extract of the plant was tested on laboratory animals for its antipyretic, analgesic, anti-inflammatory, antibacterial, purgative and muscle relaxant activities. The results of this study showed a significant antipyretic, analgesic and neuromuscular blocking activity. On smooth muscle of guinea pig ileum, the extract produced contractions which was blocked by atropine supporting its use in constipation. The extract failed to produce significant anti-inflammatory and antibacterial activities. Our phytochemical studies on the aerial parts of C. procera showed the presence of alkaloids, cardiac glycosides, tannins, flavonoids, sterols and/or triterpenes. However, the chemical constituents responsible for the pharmacological activities remains to be investigated. The safety evaluation studies revealed that the use of extract in single high doses (up to 3 g/kg) does not produce any visible toxic symptoms or mortality. However, prolong treatment (90 days) causes significantly higher mortality as compared to control group.

Evaluation of turmeric (Curcuma longa) for gastric and duodenal antiulcer activity in rats.

An ethanol extract of turmeric was studied in rats for its ability to inhibit gastric secretion and to protect gastroduodenal mucosa against the injuries caused by pyloric ligation, hypothermic-restraint stress, indomethacin, reserpine and cysteamine administration and cystodestructive agents including 80% ethanol, 0.6 M HCl, 0.2 M NaOH and 25% NaCl. An oral dose of 500 mg/kg of the extract produced significant anti-ulcerogenic activity in rats subjected to hypothermic-restraint stress, pyloruic ligation and indomethacin and reserpine administration. The extract had a highly significant protective effect against cystodestructive agents. The reduction in the intensity of ulceration of cysteamine-induced duodenal ulcers was not found to be statistically significant. Turmeric extract not only increased the gastric wall mucus significantly but also restored the non-protein sulfhydryl (NP-SH) content in the glandular stomachs of the rats.

Preliminary toxicity studies on ethanol extracts of the aerial parts of Artemisia abyssinica and A. Inculta in mice.

Ethanolic extracts of the aerial parts of Artemisia abyssinica and A. inculta were subjected to acute toxicity observations in mice for 24 h and chronic toxicity evaluation for 3 months. External morphological changes, visceral toxicity, haematological changes, spermatogenic dysfunction and effect on body weight and vital organ weight were recorded. In both the chronically treated groups, no significant acute mortality was observed up to 3 g/kg p.o. There was no weight gain in A. abyssinica chronically-treated mice while the weight gain of A. inculta-treated animals matched that of the control group. Significant sperm damage was observed in A. abyssinica-treated mice while A. inculta failed to produce any significant spermatotoxic effect.

Anti-inflammatory activity of Teucrium polium.

Teucrium polium is widely used by the folk-medicine practitioners in Saudi Arabia for the treatment of inflammations, rheumatism, diabetes and ulcers. Scientific reports are lacking to confirm these activities. The present study reports the effect of ethanolic extract of T. polium on carrageenan-induced acute inflammation, cotton-pellet granuloma and some of the biochemical parameters. The ethanolic extract of Teucrium polium at a dose of 500 mg/kg body weight produced significant inhibition of carrageenan-induced inflammation and cotton-pellet granuloma. Biochemical studies showed a significant decrease in glucose level. The presence of flavonoids and sterols might be responsible for the anti-inflammatory activity of this plant. Further studies on the fractionation of the phytoconstituents, and on their mechanism of action are in progress.

Gastroprotective activity of ginger zingiber officinale rosc., in albino rats.

The cytoprotective and gastric anti-ulcer studies of ginger have been carried out in albino rats. Cytodestruction was produced by 80% ethanol, 0.6M HC1, 0.2M NaOH and 25% NaCl. Whereas gastric ulcers were produced by ulcerogenic agents including indomethacin, aspirin and reserpine, beside hypothermic restraint stress and by pylorus ligated Shay rat technique. The results of this study demonstrate that the extract in the dose of 500 mg/kg orally exert highly significant cytoprotection against 80% ethanol, 0.6M HC1, 0.2M NaOH and 25% NaCl induced gastric lesions. The extract also prevented the occurrence of gastric ulcers induced by non-steroidal anti-inflammatory drugs (NSAIDs) and hypothermic restraint stress. These observations suggest cytoprotective and anti-ulcerogenic effect of the ginger.

Experimental studies on antirheumatic crude drugs used in Saudi traditional medicine.

A large number of herbal drugs are used in the traditional medicine of Saudi Arabia for the treatment of rheumatism, arthritis, gout and other forms of inflammation. In the present study seven of these crude drugs, namely Francoeuria crispa, Hammada elegans, Malus pumila, Ruta chalepensis, Smilax sarsaparilla, Achillea fragrantissima and Alpinia officinarum were tested against carrageenan-induced acute inflammation in rats. The plant materials were extracted with 96% ethanol. The dried extract was dissolved in water for pharmacological testing. The rats were administered an oral dose of 500 mg/kg body weight of each extract 1 h prior to production of inflammation by carrageenan injection (0.05 ml of 1% carrageenan suspension in the planter aponeurosis of the right hind foot). The paw volume was measured at 0,2,3 and 4 h after the injection. Four of the seven plants, namely Francoeuria crispa (24%), Malus pumila (23%), Ruta chalepensis (30%) and Smilax sarsaparilla (25%), produced significant inhibition of carrageenan-induced inflammation in rats. These plants also inhibited cotton pellet-induced exudation. Further studies are suggested to isolate the active principles and for the determination of the mechanism of action of these drugs.

Evaluation of Artemisia inculta for anti-inflammatory activity in rats.

The ethanolic extract of Artemisia inculta has been screened for anti-inflammatory, analgesic and antipyretic activities on suitable experimental models. It has been found to produce significant inhibition of carrageenan induced paw edema and cotton pellet induced granuloma pouch and a significant decrease in the prothrombin time in rats. It failed to produce any analgesic or antipyretic activity on the hot plate reaction time and yeast induced hypyrexia tests in mice. It also did not produce any effect on the platelet aggregation and fibrinogen level in the rats. Amongst the phytoconstituents detected in this plant, flavonoids may be responsible for the observed anti-inflammatory effect of the ethanolic extract.