CYCLOTIDES ALLOTMENT AND BIO-ACTIVITIES OF GEOPHILA HERBACEAE

Author (s) : Ms. N. ROOPA, Dr. P.POORNIMA & Ms. R. ANUPRIYA

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Abstract :
Cyclotides are an unique class of ribosomal synthesized cysteine-rich mini protein. The structure consists of a head-to-tail cyclized backbone and three conserved disulfide bonds in a knotted arrangement. Due to these structural features cyclotides are ultra-stable and have attracted interest as peptide-based templates for drug design applications. The plant families Rubiaceae, Solanaceae, Fabaceae, Cucurbitaceae, and Violaceae are known to contain cyclotides. The objective of this study is to investigate some selected plants of the family Rubiaceae for the presence of bioactive cyclotides. Initially, 17 plants of this family were screened for the presence of cyclotides using LC-MS techniques and Geophila herbaceae was selected for further study. Arial dried parts of Geophila herbaceae (140 g) was extracted with 60% aqueous methanol to yield 22 g of extract. LC-MS analysis of this extract showed the presence of about 15 different types cyclotides. Five of the cyclotides present in the mass range 2967.36+ Da to 3116.42+ Da were purified and sequenced using LC-MS-MS and were tested against microorganisms Escherichia Coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans. Out of the 5 cyclotides, 4 were inactive against all microorganisms tested at 100 µg/ml. The remaining cyclotide was active against all microorganisms at below the concentration 100 µg/ml. The cyclotides were also screened for cytotoxicity in the Fluorometric Microculture Cytotoxic Assay (FMCA) using Lymphoma U937 cells. All 5 cyclotides showed activity of 100% cell death in the range of 12.5-50 µg/ml. This study showed that Geophila herbaceae is a good source of bio-active cyclotides.

Keywords : Cyclotides, antimicrobial, cytotoxic activity.

Conference Date : 17/09/2021

Pages : 189

Paper ID : IESMDT187