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

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 H37RV 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

Polyphenolic Nutrients in Cancer Chemoprevention and Metastasis: Role of the Epithelial-to-Mesenchymal (EMT) Pathway

The epithelial-to-mesenchymal transition (EMT) has received significant interest as a novel target in cancer prevention, metastasis, and resistance. The conversion of cells from an epithelial, adhesive state to a mesenchymal, motile state is one of the key events in the development of cancer metastasis. Polyphenols have been reported to be efficacious in the prevention of cancer and reversing cancer progression. Recently, the antimetastatic efficacy of polyphenols has been reported, thereby expanding the potential use of these compounds beyond chemoprevention. Polyphenols may affect EMT pathways, which are involved in cancer metastasis; for example, polyphenols increase the levels of epithelial markers, but downregulate the mesenchymal markers. Polyphenols also alter the level of expression and functionality of important proteins in other signaling pathways that control cellular mesenchymal characteristics. However, the specific proteins that are directly affected by polyphenols in these signaling pathways remain to be elucidated. The aim of this review is to analyze current evidence regarding the role of polyphenols in attenuating EMT-mediated cancer progression and metastasis. We also discuss the role of the most important polyphenol subclasses and members of the polyphenols in reversing metastasis and targeting EMT. Finally, limitations and future directions to improve our understanding in this field are discussed