Which extractant should be used for the screening and isolation of antimicrobial components from plants

Antibacterial activity of South African plants used for medicinal purposes

Nine plants were screened for potential antibacterial activity. In evaluating antibacterial activity both aqueous and organic solvents were used. The plants screened were Sapindus emarginatus, Hibiscus rosa-sinensis, Mirabilis jalapa, Rheo discolor, Nyctanthes arbortristis, Colocasia esculenta, Gracilaria corticata, Dictyota spps., and Pulicaria wightiana. Antibacterial activity was tested against 6 bacterial strains, Pseudomonas testosteroni, Staphylococcus epidermidis, Klebsiella pneumoniae, Bacillus subtilis, Proteus morganii, and Micrococcus flavus. Two methods, Agar disk diffusion and Agar ditch diffusion, were used to study the antibacterial activity of all these plants. Ps. testosteroni and K. pneumoniae were the most resistant bacterial strains. S. emarginatus showed strong activity against the tested bacterial strains. Therefore, this can be selected for further investigation to determine its therapeutic potential. Its leaf extract can also be used as a lead molecule in combating the diseases caused by the bacterial strains studied.

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Antibacterial Activity of Some Selected Indian Medicinal Flora

Twelve medicinal plants were screened, namely Abrus precatorius L., Caesalpinia pulcherrima Swartz., Cardiospermum halicacabum L., Casuarina equisetifolia L., Cynodon dactylon (L.) Pers., Delonix regia L., Euphorbia hirta L., Euphorbia tirucalli L., Ficus benghalensis L., Gmelina asiatica L., Santalum album L., and Tecomella undulata (Sm.) Seem, for potential antibacterial activity against 5 medically important bacterial strains, namely Bacillus subtilis ATCC6633, Staphylococcus epidermidis ATCC12228, Pseudomonas pseudoalcaligenes ATCC17440, Proteus vulgaris NCTC8313 and Salmonella typhimurium ATCC23564. The antibacterial activity of aqueous and methanol extracts was determined by agar disk diffusion and agar well diffusion method. The methanol extracts were more active than the aqueous extracts for all 12 plants studied. The plant extracts were more active against Gram-positive bacteria than against Gram-negative bacteria. The most susceptible bacteria were B. subtilis, followed by S. epidermidis, while the most resistant bacteria were P. vulgaris, followed by S. typhimurium. From the screening experiment, Caesalpinia pulcherrima Swartz. showed the best antibacterial activity; hence this plant can be further subjected to isolation of the therapeutic antimicrobials and further pharmacological evaluation.

https://journals.tubitak.gov.tr/biology/issues/biy-05-29-4/biy-29-4-3-0506-4.pdf

J. Mvukiyumwami

Papers

Screening of hundred Rwandese medicinal plants for antimicrobial and antiviral properties