In vitro Antitubercular and Antibacterial activities of isolated constituents and column fractions from leaves of Cassia occidentalis, Camellia sinensis and Ananas comosus

Abstract

Background: Tuberculosis still remains a leading cause of death in the world. There is currently considerable interest in natural products and their derivatives in the area of drug research for multidrug resistant tuberculosis (MDR-TB). The present investigation focused on search for potent antitubercular and antibacterial natural leads from plants.

Objective: To evaluate isolated fractions and chemical constituents from leaves of Cassia occidentalis, Camellia sinensis and Ananas comosus for antibacterial and antitubercular activities.

Materials and Methods: Leaves were sequentially extracted with petroleum ether, benzene, chloroform, methanol and water. The obtained extracts were examined for the presence of various phytochemicals by thin layer chromatography, and then selected extracts were fractionated by column chromatography. A total of 15 column fractions were collected, and screened for antibacterial and anti-tubercular activities. The antibacterial activity was evaluated on American type cultures of Staphylococcus aureus, Bacillus subtilis, Proteus vulgaris and Pseudomonas aeruginosa by broth microdilution method, whilst anti-tubercular screening was carried out against Mycobacterium tuberculosis H₃₇R_V by microplate alamar blue assay (MABA) method.

Results: Several fractions (3, 6, 9) belong to C. occidentalis, C. sinensis showed good antibacterial activity (MIC: 2 – 8 μg/ml) and moderate antitubercular activity (MIC 25 - 50 μg/ml). Chemical constituents present in fractions 3, 6 and 9 were isolated and identified as cassiaoccidentalins, glucoronide soponin and catechin, respectively.  Fractions of A. comosus showed MIC between 16 to 32 μg/ml for antibacterial activity and > 100 μg/ml for antitubercular activity.

Discussion: Among these plants, C. occidentalis,was found to more potential against antitubercular and antibacterial activity. A. comosus was relatively less potent against antibacterial and in effective against mycobacteria. Cassiaoccidentalin exhibited potent antibacterial activity and moderate antitubercular activity.

Key words: Cassia occidentalis, Camellia sinensis, Ananas comosus, anti-tubercular activity, antibacterial activity.