Isolation and characterization of a novel flavanone glycoside from an endemic plant Haplanthodes neilgherryensis.

The chemical characterization study of an endemic plant, Haplanthodes neilgherryensisis (Wight) R.B. Majumdar from Western Ghats of India, resulted in to the isolation of a new flavanone glycoside, 5-hydroxy-7-methoxy-8-O-ß-D-glucopyranosyl-2S-flavanone (1), along with 3 known flavonoids, 7-O-methyl dihydrowogonin (2), 7-O-methyl wogonin (3), andrographidine C (4). The structure of 1 was elucidated by using 1 D and 2 D NMR and HRMS experimental data, while for the known compounds, 1H NMR and mass spectrometry data were compared with the reported literature. Compound 1 was tested in vitro to check the improvement in uptake of glucose by the L6 rat skeletal muscle tissues and the observed EC50 value was 5.8 µM, while rosiglitazone showed EC50 of 2.7 µM.

(E)-9-oxooctadec-10-en-12-ynoic acid from Ixora brachiata Roxb. increases glucose uptake in L6 myotubes by activating the PI3K pathway.

In an attempt to discover new scaffolds for anti-diabetic activity from plants, we screened extracts from Ixora brachiata Roxb. for their effect on glucose uptake in L6 myotubes. The petroleum (PE) extract of the plant showed a significant increase in insulin stimulated glucose uptake by L6 myotubes. The bioactivity guided fractionation of the crude extract yielded a compound (E)-9-oxooctadec-10-en-12-ynoic acid (OEA). The compound induced a dose dependent increase in insulin stimulated glucose uptake in L6 myotubes with an EC50 of 22.96µM. OEA also increased the phosphorylation of IRS-1, Akt and AS160 leading to increased GLUT4 translocation to the plasma membrane indicating that it promotes insulin stimulated glucose uptake in L6 myotubes by activating the PI3K pathway.

NF-κB dependent anti-inflammatory activity of chlorojanerin isolated from Saussurea heteromalla.

Medicinal plants have shown great promise as a source of novel drug compounds for the treatment of inflammatory disorders. In our search for new entities with anti-inflammatory potential, the extracts of the whole plant of Saussurea heteromalla (family-Asteraceae), collected from Himalayas, were evaluated in the high throughput screen for TNF-α and IL-6 inhibitors. The extract blocked TNF-α and IL-6 production in LPS stimulated THP-1 cells (human acute monocyte leukemia cell line) completely at 10 and 30 µg/ml. The plant has been found as a new source of chlorojanerin, a guaianolide type of sesquiterpene lactone. Chlorojanerin was shown to be significantly effective in inhibiting TNF-α and IL-6 production in LPS-stimulated THP-1 cells (IC(50)=2.3±0.2 µM and 1.8±0.7 µM respectively). The compound also blocked TNF-α and IL-6 production from LPS-stimulated human monocytes (IC(50)=1.5±0.4 and 0.7±0.2 µM respectively) and synovial cells from a patient with rheumatoid arthritis (IC(50)<0.03 and 0.5 µM respectively). Transcriptional profiling of the LPS stimulated THP-1 cells revealed that chlorojanerin exerted its anti-inflammatory effect by inhibiting the expression of 8 genes involved in activating the transcription factor - NF-κB. Real time analysis of these genes validated the effect of chlorojanerin on the classical downstream targets of NF-κB. Thus, this study clearly delineated 8 genes which were specifically mitigated due to the effect of chlorojanerin on NF-κB induced signaling at the mRNA level. Further, chlorojanerin at 5 µM also inhibited the binding of NF-κB in a GFP reporter assay system by 55.5% thus validating the microarray gene expression data. This work is a step towards the isolation and characterization of lead anti-inflammatory agents from the extract of Saussurea heteromalla, which can be developed into better therapeutic molecules targeted towards some specific inflammatory diseases.

Antiarthritic effects of Ajuga bracteosa Wall ex Benth. in acute and chronic models of arthritis in albino rats.

OBJECTIVE: To evaluate the antiarthritic activity of Ajuga bracteosa using albino rats. METHODS: The antiarthritic activity of 70% ethanolic extract of Ajuga bracteosa (EEAB) was evaluated against turpentine oil- and formaldehyde- induced acute non immunological and complete freund's adjuvant (CFA)-induced chronic immunological arthritis in albino rats. RESULTS: EEAB showed a significant (P<0.05) and dose dependent inhibitory effect against acute and chronic models of arthritis. EEAB exhibited better antiarthritic activity than the standard aspirin. CONCLUSIONS: EEAB exhibits a significant and promising antiarthritic activity against acute and chronic arthritis and supports the traditional use of Ajuga bracteosa for rheumatism and other inflammatory diseases.

Anti-inflammatory effect of Ajuga bracteosa Wall Ex Benth. mediated through cyclooxygenase (COX) inhibition.

ETHNOPHARMACOLOGICAL RELEVANCE: Ajuga bracteosa Wall Ex Benth. (Labiateae) is described in Ayurveda for the treatment of rheumatism, gout, palsy and amenorrhea. AIM OF THE STUDY: The aim of present investigation is to study anti-inflammatory activity of Ajuga bracteosa, to understand possible mechanism of action and to identify the constituents responsible for its activity. MATERIALS AND METHODS: The anti-inflammatory activity of 70% ethanolic extract was evaluated in TPA-induced mouse ear edema assay and in vitro cyclooxygenase (COX)-1 and COX-2 inhibitory activity was determined using EIA kits employing appropriate reference standards. Aajugarin I, lupulin A, withaferin A, reptoside and 6-deoxyharpagide were isolated from the 70% ethanolic extract by silica gel column chromatography. RESULTS: The 70% ethanol extract of whole plants of Ajuga bracteosa showed a significant (p<0.05) and dose-dependent anti-inflammatory activity in an acute inflammation model at the dose of 0.5 and 1.0 mg/ear. The extract also exhibited a strong in vitro COX-1 and COX-2 inhibitory activity at 25 and 50 µg/mL concentration. Among the isolated compounds 6-deoxyharpagide exhibited highest COX-2 inhibition while rest of the compounds exhibited weak to moderate COX-1 and COX-2 inhibition at 30 µM concentration. CONCLUSIONS: The results suggest that the 70% ethanol extract of Ajuga bracteosa possesses promising anti-inflammatory activity, which is possibly mediated through inhibition of COX-1 and COX-2 enzymes. The isolated constituents could be responsible in part for its anti-inflammatory and COX inhibitory activity. The study supports traditional use of Ajuga bracteosa for inflammatory diseases.

Anti-inflammatory, cyclooxygenase (COX)-2, COX-1 inhibitory and antioxidant effects of Dysophylla stellata Benth.

The n-hexane and ethyl acetate extracts of whole plants of Dysophylla stellata significantly inhibited edema when applied topically at doses of 0.5 and 1mg/ear in TPA-induced ear edema assay in mice. Further, both the extracts were evaluated for COX-1 and COX-2 inhibitory activities and showed 85.42 and 57.38%; and 71.79 and 89.27% inhibition at 50 microg/ml, respectively. Chromones (1 and 2) present in these extracts could be responsible for their COX-1 and COX-2 inhibitory and anti-inflammatory activities. The ethyl acetate extract showed antioxidant activity in DPPH and ABTS radical scavenging assay where as n-hexane extract found to be inactive.

Plant-derived compounds in clinical trials.

Plants remain an important source of new drugs, new drug leads and new chemical entities. The plant-based drug discovery resulted mainly in the development of anticancer and anti-infectious agents and continues to contribute to the new leads in clinical trials. A total of 91 plant-derived compounds in clinical trials as of September 2007 are described in this review. A summary of the plant-based drugs launched during 2000-2006 is given.

Indian medicinal plants as a source of antimycobacterial agents.

It is estimated that one-third of the world's population is infected with tubercle bacillus and the problem of tuberculosis (TB) has been intensified due to HIV pandemic providing a large reservoir of highly susceptible individuals. Since no anti-TB drugs have been introduced in past 30 years, there is an urgent need to search for and develop new, effective and affordable anti-TB drugs. In this scenario, the plant kingdom with enormous chemical diversity may be looked as an important source of new anti-TB agents. Of 17,500 higher plant species occurring in India only about 365 species have been evaluated so far for antimycobacterial activity. The present review article describes the 255 (70% of 365) plant species from a wide range of families that have shown antimycobacterial activity. The species are enumerated in table format describing plant species and family, plant part used, type of extract and in vitro activity (MIC value), information on active compounds, if any, and uses in the ethnomedicine and Ayurveda. Interestingly, most of the plant species have shown strong positive ethnopharmacological correlation with the traditional knowledge. In addition, the recent in vitro screening methods for antimycobacterial activity are also described in brief. An attempt has been made to highlight the promising plant species for further investigation as leads for drug development.