In vitro screening of Indian medicinal plants for antiplasmodial activity

Plants traditionally used in India to treat fever or malaria were examined in vitro for antiplasmodial properties against Plasmodium falciparum. Of 80 analysed ethanol extracts, from 47 species, significant effects were found for 31 of the extracts. These represent 23 different species from 20 families. Of the active species 20 were tested against P. falciparum for the first time. The following five species seems to be of special interest for further antimalarial studies, Casearia elliptica, Holarrhena pubescens, Pongamia pinnata, Soymida febrifuga, and Plumbago zeylanica.

An ethnopharmacological survey for potential angiotensin converting enzyme inhibitors from Indian medicinal plants

Plants used in different traditional systems of Indian medicine and some relatives/substitutes have been investigated for their angiotensin converting enzyme (ACE) inhibitory activity. They were selected on the basis of their usage as cardiotonics, diuretics and other uses related to the symptoms of hypertension. Out of the 73 species investigated, 22 showed more than 50% ACE inhibitory activity.

Angiotensin converting enzyme (ACE) inhibitors from Jasminum azoricum and Jasminum grandiflorum

Bioactivity-guided fractionation of extracts of the aerial parts of Jasminum azoricum var. travancorense, using an in vitro ACE inhibition assay, led to isolation of three oligomeric, iridoid-type compounds, which were named sambacein I-III. Their structures are based on spectroscopic and chemical evidence. Similarly, fractionation of extracts of aerial parts of J. grandiflorum resulted in the isolation of the previously reported ACE inhibitor, oleacein. The IC50 values of purified ACE inhibitors were 26-36 microM. Moreover, 2-(3,4-dihydroxyphenyl)-ethanol, isoquercitrin and ursolic acid were isolated from J. grandiflorum. Sambaceins and oleacein are formed from genuine iridoid glucosides during processing of the plant material. NMR spectroscopy was used to measure the level of the ACE inhibitors in the traditional medicines prepared in Kerala from these Jasminum species.

Quantitative determination of thapsigargins in roots and fruits from Thapsia gymnesica

Three sesquiterpene lactones, thapsigargin, thapsigargicin, and nortrilobolid, and 6-methoxy-7-geranyloxycoumarin have been isolated from the roots of Thapsia gymnesica (Apiaceae) for the first time. The concentrations of the three thapsigargins in the roots and the fruits have been determined by HPLC analysis.

Antimicrobial screening of selected medicinal plants from India

From the Indian traditional medicines 78 plants were selected on the basis of their use in the treatment of infectious diseases. Different concentrations of 80% ethanol extracts were tested, using the agar dilution method, against four bacteria: Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa and, using the agar-well diffusion method, against two fungi: Candida albicans and Aspergillus niger. In the lowest tested concentration of 1.6 mg/ml, 10% of the plant extracts were active; 44% in a concentration of 6.25 mg/ml and 90% of the plant extracts were active against at least two bacteria in a concentration of 25 mg/ml. Only 13% of the plant extracts were active against at least one fungus in a concentration of 50 mg/ml.

Isolation of angiotensin converting enzyme (ACE) inhibiting triterpenes from Schinus molle

Bioactivity-guided fractionation of extracts of Schinus molle leaves, using an in vitro assay, led to the isolation of ACE-inhibitory steroidal triterpenes of the euphane type, identified by means of NMR spectroscopic methods. One of the triterpenes was isolated as an equilibrium mixture of epimeric aldehydes. The triterpenes showed moderate ACE-inhibitory activity (IC(50) about 250 microM).

New anti-HIV-1, antimalarial, and antifungal compounds from Terminalia bellerica

A bioactivity-guided fractionation of an extract of Terminalia bellerica fruit rind led to the isolation of two new lignans named termilignan (1) and thannilignan (2), together with 7-hydroxy-3',4'-(methylenedioxy)flavan (3) and anolignan B (4). All four compounds possessed demonstrable anti-HIV-1, antimalarial, and antifungal activity in vitro.

Essential oils from fruits of three types of Thapsia villosa

Thapsia villosa has been divided into five types and previous analyses of the essential oils from the fruits of two of these types showed that limonene and methyl eugenol were the major constituents. The composition of the essential oils from the fruits of the other three types of T. villosa, with the chromosome numbers 2n = 22 (2x), 2n = 22 (2x) and 2n = 44 (4x), is reported here. The oil from all three types shows a similar chemical profile, with geranyl acetate as the main constituent accounting for 78-92% of the total oil. The composition of the essential oils from these plants is clearly different from the first two types of T. villosa mentioned, and also from the other species within the genus Thapsia.

Angiotensin converting enzyme (ACE) inhibitory flavonoids from Erythroxylum laurifolium

In our screening program for antihypertensive properties of plants in traditional use, the 99% ethanol extract of Erythroxylum laurifoiium leaves showed interesting angiotensin converting enzyme (ACE) inhibitory activity. The activity was found to be due to proanthocyanidins or condensed tannins and the flavonoids quercetin-3-O-rhamnoside (quercitrin) (IC(50) = 0.67 mM) and kaempferol-3-O-rhamnoside (afzelin) (IC(50) = 2.8 mM). In addition, quercitrin with afzelin demonstrated in vitro synergistic ACE inhibitory activity.

In vitro screening of traditional medicines for anti-hypertensive effect based on inhibition of the angiotensin converting enzyme (ACE)

Traditional medicines reported to be used as anti-hypertensives or diuretics from different regions in the world (China, India and South America) have been investigated. The bioassay is based on inhibition of ACE, as measured from the enzymatic cleavage of the chromophore-fluorophore-labelled substrate dansyltriglycine into dansylglycine and diglycine. In total, 31 species have been investigated and the crude extracts from seven species inhibit the enzyme by more than 50%.

Somatic embryogenesis in cell cultures of Thapsia garganica : Correlation between the state of differentiation and the content of thapsigargins

Cell cultures from different species of the genus Thapsia (Apiaceae) have been investigated. In one 4-yearold line of T. garganica L. spontaneous somatic embryogenesis up to the globular stage occurred in a suspension culture containing 1 mg l(-1)2,4-dichlorophenoxyacetic acid (2,4-D). Also callus cultures of this line, previously maintained on a medium containing 1 mg l(-1) 2,4-D, when transferred to various media deprived of 2,4-D, produced somatic embryos that developed into plantlets. Cell culture, embryos and regenerated organs were analysed for their content of thapsigargins. The undifferentiated cell culture did not synthezise thapsigargins, but was found to produce a yet unidentified compound not present in planta. White embryos in the pre-cotyledonary stage did not synthezise thapsigargins either, but when the embryos developed to the cotyledonary stage and became green, the synthesis started. Regenerated roots and shoots also contained thapsigargins.