Anti-bacterial studies on Hemigraphis colorata (Blume) H.G. Hallier and Elephantopus scaber L.

OBJECTIVE: To examine the ethanol, aqueous, chloroform, benzene, acetone and petroleum ether extracts of, Hemigraphis colorata (H. colorata) leaves and stem and Elephantopus scaber (E. scaber) leaves, root and flower for the presence of phyto-constituents and screened the anti-bacterial activity against the selected pathogens. METHODS: The fresh materials were shade dried and powdered using the tissue blender. The dried and powered materials (50 g) were extracted successively with 200 mL of aqueous, acetone, benzene, chloroform, ethanol, and petroleum ether by using Soxhlet extractor for 8 h at a temperature not exceeding the boiling point of the solvent. Aqueous, acetone, benzene, chloroform, ethanol, and petroleum ether extracts were prepared from powdered materials were used for preliminary phytochemical and antimicrobial studies using standard methods. RESULTS: The crude aqueous, acetone, benzene, chloroform, ethanol, and petroleum ether extracts E. scaber leaves, flower and root and H. colorata leaves and stem demonstrated that out of (5×6×12 = 360) tests for the presence or absence of the above compounds, 188 tests gave positive results and the remaining 172 gave negative results. The results of the phytochemical screening revealed that phenol (12/12), carbohydrates (9/12), steroids (8/12), saponins and coumarins (7/12), tannins (6/12), proteins (5/12), carboxylic acid and flavonoids (4/12), xanthoproteins (3/12) and alkaloids (2/12) presence in the crude aqueous, acetone, benzene, chloroform, ethanol, and petroleum ether extracts of H. colorata leaves and stem. The crude aqueous, acetone, benzene, chloroform, ethanol, and petroleum ether extracts E. scaber leaves, flower and root displayed the presence of phenol (18/18), tannin (17/18), carbohydrates (16/18), steroids (14/18), carboxylic acid and coumarins (12/18), saponins (10/18), xanthoprotein (9/18), flavonoids (7/18), protein (4/18) and alkaloids (2/18). The root ethanolic extracts of E. scaber illustrated the highest zone of inhibition against three pathogens viz., Staphylococcus aureus (S. aureus) (24 mm), Escherichia coli (E. coli) (16 mm) and Pseudomonas aeruginosa (P. aeruginosa) (13 mm). The chlorofrom extracts of E. scaber showed the highest zone of inhibition against Bacillus cereus (B. cereus) (12 mm), The leaves ethanolic extracts of E. scaber demonstrated the highest zone of inhibition against three pathogens viz., Enterococcus faecalis (E. faecalis) (18 mm), Proteus mirabilis (P. mirabilis) (17 mm), Salmonella Typhi (S. typhi) (14 mm) and Enterobacter sp. (11 mm) While the benzene extracts of H. colorata demonstrated maximum zone of inhibition against the pathogen Acinetobacter sp. (14 mm) and S. aureus (12 mm). CONCLUSIONS: It is hoped that this study would direct to the establishment of some compounds that could be used to invent new and more potent antimicrobial drugs of natural origin.

Preliminary phytochemical studies of the leaf extracts of Rhododendron arboreum Sm. ssp. nilagiricum (Zenker) Tagg

Objective: To examine the secondary metabolites present in the leaf extracts of Rhododendron arboreum Sm. ssp. nilagiricum (Zenker) Tagg. Methods: Phytochemical screening of the leaf extract was done to determine the phytochemical constituents in the various solvents studied.Results:nilagiricum (Zenker) Tagg. confirm the existence of secondary metabolites such as phenols, saponins and tannins. Conclusions: The study suggests that the leaf extracts of R. arboreum Sm. ssp. nilagiricum (Zenker) Tagg. can be best utilized in developing bioactive compounds against pathogenic infection. The phytochemical study carried out on the leaf extracts of R. arboreum Sm. ssp.

Antibacterial activity of selected ethnomedicinal plants from South India.

OBJECTIVE: To screen the antimicrobial potential of three ethnomedicinal plants Chassalia curviflora Thw. (C. curviflora), Cyclea peltata Hook. F. & Thomson (C. peltata) and Euphorbia hirta L (E. hirta) used in folk medicines in Aarukani hills Kani tribe, Tamil Nadu, India against human bacterial pathogens. METHODS: Antibacterial efficacy was performed by disc diffusion method against the pathogens viz., Escherichia coli (E. coli) (ATCC 35218), Staphylococcus aureus (S. aureus) (ATCC 6538), Salmonella typhi (S. typhi) (MTCC 733), Proteus vulgaris (P. vulgaris), Proteus mirabilis (P. mirabilis) and Streptococcus pyogenes (S. pyogenes) and incubated for 24 h at 37 °C. RESULTS: The maximum degree of antibacterial activity was observed in C. peltata followed by C. curviflora. While E. hirta showed comparatively low degree of antibacterial activity. The methanolic extract of C. peltata showed the antibacterial activity against three pathogens viz., S. pyogenes, P. vulgaris and E. coli with the inhibition zones 12 mm, 10 mm and 9 mm, respectively. hexane extracts of C. peltata also showed the antibacterial activity against two selected pathogens viz., P. vulgaris and P. mirabilis with 15 mm and 12 mm of inhibition zones. All the three different concentrations (0.25, 0.50 & 0.75 mg/mL) of methanolic extract of C. peltata show the inhibitory effect on the three susceptible bacteria S. pyogenes, P. vulgaris and E. coli with the maximum inhibition in the highest concentration (0.75 mg/mL). The methanolic and hexane extracts of C. curviflora exhibited the antibacterial activity against only one bacterium each i.e. P. vulgaris and S. typhi with the maximum zone of inhibition 13 and 11 mm respectively. The methanolic and hexane extracts of E. hirta exhibited the antibacterial activity against only one bacterium i.e. S. pyogenes with the maximum zone of inhibition 13 and 11 mm respectively. CONCLUSIONS: The present investigation revealed that the C. curviflora, C. peltata and E. hirta are potentially good source of antibacterial agents and demonstrates the importance of such plants in traditional medicines.

Phytochemical studies on Azolla pinnata R. Br., Marsilea minuta L. and Salvinia molesta Mitch

Objective: To evaluate the phytochemical properties of Azolla pinnata R. Br., Marsilea minuta L. and Salvinia molesta Mitch. Methods: The dried and powered leaves materials (50 g) were extracted successively with 250 mL of petroleum ether, ethyl acetate, methanol, chloroform, acetone, benzene and water by using Soxhlet extractor for 8 h at a temperature not exceeding the boiling point of the solvent. Phytochemical screening of the extracts was carried out according to the standard methods. Results: Out of eighteen tested extracts, eighteen extracts showed the presence of phenolics. Next to that, fourteen extracts were illustrated their existence of tannin. Ten extracts showed the occurrence of carbohydrates in the crude extracts of the selected plants. Steroid and saponin are present in eight extracts, next to that xanthoprotein is present in six extracts, followed by flavonoid and protein which are present in five extracts. Carboxylic acid showed its presence only in two extracts. Conclusions: From the results, it can be concluded that the three plants extracts show the presence of many bioactive compounds after extensive investigation. We recommend further research on these plants to quantify the concentration of these compounds. Further work will accentuate the isolation and characterization of active principles responsible for bio-efficacy and bioactivity.

Preliminary phytochemical screening of the pericarp of Crataeva magna (Lour.) DC. - a medicinal tree

Objective: To examine the phytochemicals present in the pericarp of Crataeva magna (C. magna) (Lour.) DC. which is used as a traditional medicine by the inhabitants of Kanyakumari district. Methods: Phytochemical screening of the pericarp was done to determine the secondary metabolites in various solvents studied. Results: The phytochemical screening on the pericarp of C. magna (Lour.) DC. proved the presence of phytochemicals such as phenols, saponins and tannins. Conclusions: The findings of the present study recommended that the pericarp of C. magna (Lour.) DC. have potential antimicrobial compounds that may be of use for developing plant based drugs for various ailments.

Myrica esculenta Buch.-Ham. ex D. Don.-a potential ethnomedicinal species in a subtropical forest of Meghalaya, northeast India

Objective: To determine the effect of anthropogenic activities on the population structure and regeneration efficacy of Myrica esculenta (M. esculenta), an ethnomedicinally important tree species in sub-tropical forests of Meghalaya. Methods: The population structure and regeneration potential of M. esculenta were studied by using quadrat method. Results: The regeneration status of M. esculenta was highly influenced by disturbance. Presence of limited number of seedlings in the forest floor denotes the lack of seeds in the forests. The low conversion of seedling into saplings was mainly due to the removal saplings by the indigenous community, who residing in the vicinity of the forest for meeting their requirement of fuel wood. Conclusions:The findings of the present study indicate that overexploitation of M. esculenta may cause threat to extinction from wild. There is an obvious need to explore non timber forest products to a desired pace that will minimize the pressure on a particular species by providing alternative to a species, leading to sustainable utilization of genetic resources.

Antimicrobial activity of certain fresh water microalgae from Thamirabarani River, Tamil Nadu, South India

Objective:To evaluate the antimicrobial potential of fresh water microalgae viz., Oscillatoria sancta (O. sancta) (Kuetz) Gomont., Lyngbya birgei (L. birgei) Smith G.M., Oedogonium echinospermum (O. echinospermum), Spirogyra decimina (S. decimina) (Muller) Kuetz., Spirogyra grantiana (S. grantiana) Transeau., Spirogyra crassa (S. crassa), Spirogyra biformis (S. biformis) Jao. and Spirogyra condensata (Vaucher) Kuetz against human bacterial pathogens. Methods:Antimicrobial study was carried out by disc diffusion method against the pathogens viz., Escherichia coli (E. coli) (ATCC 35218), Staphylococcus aureus (S. aureus) (ATCC 6538), Salmonella typhi (S. typhi) (MTCC 733), Proteus vulgaris (P. vulgaris), Proteus mirabilis (P. mirabilis) and Streptococcus pyogenes. Results: The methanolic extract of O. sancta showed the antibacterial activity against three pathogens viz., P. mirabilis, P. vulgaris and S. aureus with the inhibition zones of 10, 8 and 8 mm, respectively. The methanolic and ethanolic extracts of L. birgei exhibited the antibacterial activity against two pathogens i.e. P. mirabilis and P. vulgaris with the maximum zone of inhibition of 8 and 8 mm, respectively. The ethanolic extracts of O. echinospermum displayed the antibacterial activity against S. typhi and P. mirabilis with the maximum of zone of inhibition (7 mm). The methanolic extracts of S. decimina exhibited the antibacterial activity against S. aureus and P. mirabilis with the maximum zone of inhibition of 12 and 9 mm, respectively. The ethanolic extracts of S. grantiana showed the anti-bacterial activity against three organisms i.e. E. coli, P. vulgaris and P. mirabilis with the zone of inhibition of 9, 10 and 9 mm, respectively. The methanolic extracts of S. crassa exhibited the antibacterial activity against P. mirabilis with the maximum zone of inhibition (9 mm). The methanolic extracts of S. biformis exhibited the antibacterial activity against P. vulgaris with the maximum zone of inhibition (8 mm). Conclusions: These results give an indication of the presence of promising antibacterial compounds in the plants under studied. Further phytochemical studies are needed to elucidate the components responsible for antibacterial activity of these extracts against bacteria.