IN VITRO EVALUATION OF THE ANTIMICROBIAL, TOXIC, ANTI-ARTHRITIC AND THROMBOLYTIC PROPERTIES OF DIFFERENT PARTS OF PLANT ORCHID RHYNCHOSTYLIS RETUSA (L.) BLUME.

Abstract

Background: Infection due to microbes, trauma, cancer, arthritis and thrombosis are the most common problems worldwide. Traditionally, a large number of herbal extracts are used for the treatment of those disorders. Aim: Ethanolic extracts from leaves, roots and stems of Rhynchostylis retusa (L.) Blume were phytochemically characterised and then tested for their antibacterial, toxicity, anti-arthritic, and thrombolytic properties in-vitro. Methods and Results: Disk diffusion inhibition tests with a panel of fourteen different microorganisms was used as the antimicrobial assays. Antimicrobial activity of the stem extract found to be higher (10-11 mm, 400 µg/disk) than that of root extract whereas leaf showed no activity with ciprofloxacin (43-46 mm, 5 µg/disc) serving as reference standard. Toxicity of the plant extracts in terms of their LC50 values against the brine shrimp (A. salina) was assessed. The toxic potential of leaf extract was 6.7 μg/ml, which is higher than that of stem and root extract (c.a. 8.5 μg/ml). Thrombolytic properties were tested in vitro using streptokinase as reference (%Clot lysis after 1.5h & 24h was 76.15±1.94 & 92.59±2.35, 30000iu). The leaf extract exhibited higher activity. Leaf extract (1000 ppm) lysed of 33.08±1.24% of the clot and 60.47±2.33 after 1.5 h and 24 h of incubation, respectively. Anti-arthritic effects measured as albumin denaturation using diclofenac sodium as reference (IC50=60.25 ppm) revealed the stem extract as more active. Conclusion: our research will help to provide evidence for some of the traditional uses of this medicinal plant