Purification and characterization of charantin, a napin‐like ribosome‐inactivating peptide from bitter gourd (Momordica charantia) seeds

Abstract

A peptide designated charantin, with a molecular mass of 9.7 kDa, was isolated from bitter gourd seeds. The procedure comprised affinity chromatography on Affi-gel blue gel, ion-exchange chromatography on Mono S and gel filtration on Superdex 75. The N-terminal sequence of charantin exhibited marked similarity to that of the 7.8-kDa napin-like peptide previously isolated from bitter gourd seeds. Charantin inhibited cell-free translation in a rabbit reticulocyte lysate system with an IC50 of 400 nm, a potency lower than that of the previously reported small ribosome-inactivating protein gamma-momorcharin (IC50 = 55 nm) which also exhibited an abundance of arginine and glutamate/glutamine residues. Charantin reacted positively in the N-glycosidase assay, yielding a band similar to that formed by the small ribosome-inactivating proteins gamma-momorcharin and luffin S.

Expression of a Novel Small Antimicrobial Protein from the Seeds of Motherwort ( Leonurus japonicus ) Confers Disease Resistance in Tobacco

“…However, some napin-like proteins were reported to be single-chain proteins. For instance, charantin, an RIP isolated from balsam pear, is a single-chain peptide and structurally related to the large chain of the napin-like proteins (36). Although the major function of napins is devoted to storage (4), some napins or napin-like proteins possess significant antifungal or antibacterial properties (4,32).…”

Induction of Interferon-Gamma (IFN-γ) and T Helper 1 (Th1) Immune Response by Bitter Gourd Extract

“…Bitter gourd contains momordicin, a glucoside-like substance that can lower blood glucose [9]. Steroids extracted from charantin, a stigmasterol, are protein alkaloid complexes with insulin-like effects [12,13]. In addition, bitter gourd seeds have been shown to be effective in treatment of cancer [16].…”

α-Glucosidase Inhibitory Effect of Vicine and α-Eleostearic Acid from the Seeds of Momordica charantia

“…여주에서 다양한 생리활성을 나타내는 성분들이 보고되고 있는데, 구성성분으로는 essential oil, flavonoid, phenolic acid, triterpene 및 alkaloid 등이 알려져 있다 (Liu et al, 2009;Singh et al, 2012;Kenny et al, 2013;Kim et al, 2013). 특히 여주의 과실에 함유되어 있는 triterpene glycoside인 charantin이라는 성분은 췌장의 ß세포에 작용 하여 인슐린의 분비를 촉진함으로써 혈당을 낮춰 주는 역할 을 하는 것으로 보고되고 있다 (Parkash et al, 2002;Rathi et al, 2002;Schmourlo et al, 2005). 또한 alkaloid계 vicine이라는 성분과 polypeptide-p라는 식물 인슐린 (vegetable insulin) 역시 혈당강하에 효과가 있는 것으로 널리 알려져 있지만 (Khanna et al, 1981) 여주 과실 이외의 다른부위 특히, 씨(종자)의 주요 생리활성물질 및 혈당개선의 효과에 대한 연구는 거의 없는 실정이다.…”