Plectranthus : A review of ethnobotanical uses

Medicinal plants have many traditional claims including the treatment of ailments of infectious origin. In the evaluation of traditional claims, scientific research is important. The objective of the study was to determine the presence of antibacterial activity in the crude extracts of some of the commonly used medicinal plants in Malaysia, Andrographis paniculata, Vitex negundo, Morinda citrifolia, Piper sarmentosum, and Centella asiatica. In this preliminary investigation, the leaves were used and the crude extracts were subjected to screening against five strains of bacteria species, Methicillin Resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli, using standard protocol of Disc Diffusion Method (DDM). The antibacterial activities were assessed by the presence or absence of inhibition zones and MIC values. M. citrifolia, P. sarmentosum and C. asiatica methanol extract and A. paniculata (water extract) have potential antibacterial activities to both gram positive S. aureus and Methicillin Resistant S. aureus (MRSA). None of the five plant extracts tested showed antibacterial activities to gram negative E. coli and K. pneumoniae, except for A. paniculata and P. sarmentosum which showed activity towards P. aeruginosa. A. paniculata being the most potent at MIC of 2 g/disc. This finding forms a basis for further studies on screening of local medicinal plant extracts for antibacteria properties.

In vitro screening of five local medicinal plants for antibacterial activity using disc diffusion method.

This is an erect, branching shrub of the VERBENACEAE family, 0.5 to 2 m high. Stems are 4-angled, armed with hooked prickles. Leaves opposite, blade ovate, 4 to 10 cm long, with coarse surfaces and toothed margins. Flowers are dense, longstalked, flat-topped, head-like, axillary spikes about 2.5-cm across. The corolla is sympetalous, with a curved tube and a spreading limb about 8 mm wide; yellow, orange, red or pink in color. Fruit is a shiny, dark purple or black, globose drupe, 5 to 6 mm wide.

Lantana camara L

The modern antibiotic era can be said to have opened on February 12, 1941, with the first clinical trial of penicillin. Within a couple of years man had at last, after eons of adventitious searching, a truly effective and safe agent for the treatment of many systemic bacterial infections. This was shortly followed by the introduction of one after another of the major antibiotic substances which remain the mainstay of clinical therapy of infectuous diseases to this date. Intensive screening of fermentation liquors derived from various microbes, principally fungi and streptomycetes, has resulted in literature descriptions of more than 2,000 Individual antibiotics to date, and It has been estimated that more than 20,000 analogs of 6-amino- penicillante acid alone have been made by chemists working tn close collaboration with biochemists and microbiologists. Several of these substances are currently on the market.

Antimicrobial Agents from Higher Plants

Hypoglycemic and antidiabetic effect of ethanolic extract of leaves of Annona squamosa L. in experimental animals.

Three hundred botanically identified plant materials have been extracted with 50% ethanol and the extracts put through a wide biological screen. These include tests for antibacterial, anticancer, antifertility, antifungal, anthelminthic, antiprotozoal, antiviral and pharmacological activities. Biological activities have been confirmed in fractions of fifty-six of these extracts.

O S Bhakuni

Papers

Screening of indian plants for biological activity. part-ii