Antidiabetic activity of medium-polar extract from the leaves of Stevia rebaudiana Bert. (Bertoni) on alloxan-induced diabetic rats.

OBJECTIVE: To investigate the medicative effects of medium-polar (benzene:acetone, 1:1, v/v) extract of leaves from Stevia rebaudiana (family Asteraceae) on alloxan-induced diabetic rats. MATERIALS AND METHODS: Diabetes was induced in adult albino Wistar rats by intraperitoneal (i.p.) injection of alloxan (180 mg/kg). Medium-polar extract was administered orally at daily dose of 200 and 400 mg/kg body wt. basis for 10 days. The control group received normal saline (0.9%) for the same duration. Glibenclamide was used as positive control reference drug against Stevia extract. RESULTS: Medium-polar leaf extract of S. rebaudiana (200 and 400 mg/kg) produced a delayed but significant (P < 0.01) decrease in the blood glucose level, without producing condition of hypoglycemia after treatment, together with lesser loss in the body weight as compared with standard positive control drug glibenclamide. CONCLUSIONS: Treatment of diabetes with sulfonylurea drugs (glibenclamide) causes hypoglycemia followed by greater reduction in body weight, which are the most worrisome effects of these drugs. Stevia extract was found to antagonize the necrotic action of alloxan and thus had a re-vitalizing effect on ß-cells of pancreas.

Isolation and structure determination of acetylated triterpenoid saponins from the seeds of Centratherum anthelminticum.

Phytochemical investigation of Centratherum anthelminticum seeds resulted in the isolation of two novel glycosides. The pentacyclic triterpenoid saponins were shown to contain hederagenin and sugar residues forming two glycosyl chains. The structural analysis of its acetylated derivative was determined using a combination of homo- (1D 1H NMR, 13C NMR and 13C NMR-DEPT) and heteronuclear 2D NMR techniques (1H-1H-COSY, total correlated spectroscopy (TOCSY), heteronuclear multiple quantum coherence (HMQC)), heteronuclear multiple bond correlation (HMBC) and chemical methods. The structure of the saponins were established to be 3-O-[beta-D-glucopyranosyl-(1 --> 2)-alpha-L-rhamnopyranosyl-(1 --> 2)-alpha-L-arabinopyranosyl]-28-O-[beta-D-xylopyranosyl-(1 --> 4)-alpha-L-rhamnopyranosyl-(1 --> 3)-beta-D-glucopyranosyl]-23-hydroxyolean-12-en-28-oic acid and 3-O-[beta-D-glucopyranosyl-(1 --> 2)-alpha-L-rhamnopyranosyl-(1 --> 2)-alpha-L-arabinopyranosyl]-28-O-[beta-D-glucoyranosyl-(1 --> 3)-beta-D-glucopyranosyl]-23-hydroxyolean-12-en-28-oic acid. Different extracts and compounds were also tested for antifilarial and antimicrobial activities. Methanolic, acetone and aqueous extracts of seeds exhibited some pronounced pharmacological activity under study.

New principles from seeds of Nigella sativa.

A new triterpene saponin and known steroidal glucoside were isolated from the alcohol extract, and a new cycloartenol from n-hexane extract of seeds of Nigella sativa L. and were identified as 3-O-[beta-D-xylopyranosyl-(1-->2)-alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl]-11-methoxy-16,23-dihydroxy-28-methylolean-12-enoate (1), stigma-5,22-dien-3-beta-D-glucopyranoside (2) and cycloart-23-methyl-7,20, 22-triene-3beta,25-diol (3), respectively. They were characterised on the basis of spectral analysis and comparison with literature data. The hexane and alcohol extract of the seeds showed antimicrobial activity. The antioxidant activity of hexane extract is also described.

Novel steroids from the seeds of Centratherum anthelminticum.

Two novel and two known steroids were isolated respectively from benzene: acetone and ethanolic extracts of the seeds of C. anthelminticum and, identified as (24alpha/R)-Stigmasta-7-en-3-one (1), (24alpha/R)-Stigmasta-7, 9(11)-dien-3-one (2), (24alpha/S)-Stigmasta-5, 22-dien-3beta-ol (3) and (24alpha/S)-Stigmasta-7, 22-dien-3beta-ol (4). The structures were assigned on the basis of their IR, 1H NMR, 13C NMR (DEPT), 2D NMR (1H-1H COSY and 1H-13C COSY), mass spectra, chemical analyses and on comparison with literature values. The novel steroids (1) and (2) were also tested against several human pathogenic bacteria and fungi.

Structure elucidation by NMR spectroscopy of a new acetylated saponin from Centratherum anthelminticum.

A new glycosylated triterpene has been isolated from the seeds of Centratherum anthelminticum, a medicinally important plant. The structural analysis of its acetylated derivative was performed by 1H, 13C NMR, 1H-1H COSY, HMQC, HMBC and DEPT spectroscopy. The saponin was shown to contain hederagenin and six sugar residues forming two glycosyl chains. The complete structure of the saponin was established as 3-O-[beta-D-glucopyranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl]-28-O-[beta-D-glucuronopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->3)-beta-D-glucopyranosyl]-hederagenin.

Triterpenoids from the stembark of Pyrus communis.

Three triterpenoids were isolated from the stem bark of Pyrus communis Linn. and identified as lup-20(29)-ene-3alpha, 27-diol (1), lup-20(29)-ene-3alpha-ol (2) and lup-20(29)-ene-3alpha, 28-diol (3) on the basis of spectral and chemical analysis. The Compound (1) is a novel triterpene, being reported first time by us.

The antimicrobial efficiency of Piper betle Linn leaf (stalk) against human pathogenic bacteria and phytopathogenic fungi.

The in vitro antimicrobial activity of different varieties of Piper betle Linn, leaf stalk extracts were studied against human pathogenic bacteria and phytopathogenic fungi by comparing the results with standard microbial susceptibility testing biodiscs. The ethyl acetate and ethanol extracts of all the four varieties have shown significant activity against bacteria Vibrio cholerae ogawa, Staphylococcus aureus, Diplococcus pneumoniae and Klebsiella aerogenes. The hexane and benzene extracts have shown moderate activity, while other extracts have shown poor or no activity. In the same way ethyl acetate and ethanol extracts of all the varieties have shown moderate to significant activity against most of the fungi tested, while other extracts showed poor or moderate activity.

Antifilarial activity of Centratherum anthelminticum seed extracts on Setaria cervi.

Effect of aqueous and alcoholic extract of C. anthelminticum was studied on the spontaneous movements of the whole worm and nerve-muscle preparation of S. cervi. Ethylacetate, acetone and methanol extract showed similar effect, of causing inhibition of spontaneous motility of the nerve-muscle preparation of S. cervi characterized by decreased amplitude and frequency of contractions. The inhibitory effect on the motility was reversible. Further, the extracts did not involve the blockade of cholinergic receptors as evidenced by the presence of unaltered stimulant response of acetylcholine in the presence of drug in bathing fluid.

In vitro antimicrobial efficacy of Centratherum anthelminticum seeds extracts.

The in vitro antimicrobial efficacy of different extracts of seeds of Centratherum anthelminticum was studied by the filter paper disk method against several human pathogenic bacteria and fungi. Some of the extracts showed significant effect over tested bacteria and fungi.

Isolation and in vitro antimicrobial efficiency of Butea monosperma seed oil on human pathogenic bacteria and phytopathogenic fungi.

The in vitro antimicrobial efficiency of seed oil of Butea monosperma was studied by the filter paper disk method against several human pathogenic bacteria and fungi. The oil showed a significant bactericidal and fungicidal effect.