JOURNAL OF AGRICULTURE & SOCIAL SCIENCES ISSN Print: 1813–2235; ISSN Online: 1814–960X 11–014/AWB/2012/8–1–24–28 http://www.fspublishers.org Full Length Article To cite this paper: Mahalel, U.A., 2012. Antibacterial sensitivity for some chemically diverse steroidal glycosides in vitro. J. Agric. Soc. Sci., 8: 24–28 Antibacterial Sensitivity for some Chemically Diverse Steroidal Glycosides In Vitro USAMA A. MAHALEL 1 Botany Department, Aswan Faculty of Science, South Valley University, Aswan 81528, Egypt 1 Corresponding author’s e-mail: mahalel71@yahoo.com ABSTRACT Antimicrobial sensibility of steroids and steroidal glycosides are being studied widely. The in vitro susceptibilities of the steroidal glycosides were tested against Bacillus cereus, Staphylococcus aureus, Serratia marcescens, Escherichia coli and Pseudomonas putida using the disc diffusion method. These steroidal glycosides were identified as alpinoside C (1) [kidjolanin3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyranosyl-(1→4)-β-D-oleandropyranosyl-(1→4)-β-D-cymaropyranosyl -(1→4)-β-D-cymaro-pyranoside]; Ghalakoside (2) [cardiac glycoside] and pentandroside A (3) [(22S,25S)-16,22,26- trihydroxycholest-4-en-3-one-16-O-β-D-glucopyranosyl-(1→3)-α-D-xylopyranoside], which were isolated from Oxystelma esculentum var. alpine; Pergularia tomentosa and Tribulus pentandrus, respectively. Almost all of the selected compounds produced significant antibacterial potentialities against all tested microorganisms and the data were compared to the standard antibiotics. All compounds exhibited remarkable susceptibilities against Gram negative (S. marcescens) and Gram positive (B. cereus). The minimum inhibitory concentrations (MIC) of compounds ranged from 10 to 50 μg/disc. © 2012 Friends Science Publishers Key Words: Antibacterial sensitivity; Medicinal plants; Polyhydroxypregnane ester glycoside; Cardiac glycoside; Cholestane glycoside INTRODUCTION There is a general tendency to use the metabolites of plant extracts for treatment of diseases allover the world. Steroidal glycosides represent a diverse group of metabolites exhibiting a wide range of biological activities due to their antioxidant properties and ability to modulate several enzymes or cell receptors (Kintia et al., 1986) [1]. As a part of our ongoing study of various Egyptian medicinal plants, we isolated some new steroidal glycosides from Oxystelma esculentum var. alpine (Hamed et al., 2004a) Pergularia tomentosa (Al-Said et al., 1988; Hamed et al., 2006) and Tribulus pentandrus (Hamed et al., 2004b). The resistance of pathogenic organisms towards drugs has become a serious problem in the last decades. Therefore, there is an urgent need to discover new compounds possessing potent antimicrobial activities for developing new drugs. Many antimicrobial agents have been introduced into therapy; however the field still needs extensive efforts for the development of new antimicrobial agents of superior activity and less toxicity. Development of new antibacterial agents (natural or synthetic) can be useful in the control of infections caused by pathogenic micro-organisms. As a matter of fact, phytochemicals were reported to inhibit a number of micro-organisms (Fisher et al., 1984; Gurney & Mantle, 1993; Venera et al., 2009; Zaixiang et al., 2010). Moreover, antibacterial activity of steroidal glycosides has been extensively reviewed (Tamura, 1996; Takeya, 1997; Gibbons, 2005). The objective of the present work was to verify, in vitro, the antibacterial susceptibility of the major constituent of the steroidal glycosides isolated from the selected plants such as alpinoside C, ghalakoside and pentandroside A. MATERIALS AND METHODS Plant materials: All plant materials were identified according to Tàckholm (1974) and Boulos (2000), and the voucher specimens were deposited in Faculty of Science Herbarium at Aswan. The aerial parts of O. esculentum var. alpine (No. 010497) were collected from conservation Gazal Island, Aswan, Egypt, in December 2001; the root parts P. tomentosa L (No.010889) were collected from Wadi Um Hebal (Wadi Allaqi road Eastern Desert, Aswan- Egypt), in January 2001 and the aerial parts of T. pentandrus Forssk. (No. 11030) were collected in December 2001 from Wadi Allaqi Eastern Desert, Aswan-Egypt (Table I). Extraction and isolation of alpinoside C (1): The alpinoside C (1) was isolated from the dried aerial parts (1350 g) of O. esculentum var. alpine and identified by using extensive spectroscopy methods (Hamed et al., 2004a).