Isolation and Structure Identification of Bioactive Compounds from Leaves and Twigs Of

ISOLATION AND STRUCTURE IDENTIFICATION OF BIOACTIVE COMPOUNDS FROM LEAVES AND TWIGS OF Garcinia succifolia Kurz (GUTTIFERAE)

Rangsinee Hamkool1,*, Pawinee Piyachaturawat2, Surawat Jariyawat2, Kanoknetr Suksen2, Darunee Soorukram1, Manat Pohmakot1 , Vichai Reutrakul1, Patoomratana Tuchinda1

1Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.

2Department of Physiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.

*e-mail: , #e-mail: .

Abstract

Plants of the genus Garcinia were found to possess a wide range of biological activities, such as antimicrobial, cytotoxic, antitumor, antimalarial, antifungal and antioxidant activities. Garcinia succifolia Kurz (Guttiferae) is an endemic plant, found in Northern Thailand (Chiang Mai Province). Therefore, we are interested in the isolation and identification of compounds from a methanol extract of leaves and twigs. The crude extracts, fractions and isolated pure compounds were evaluated for their cytotoxic activities against a panel of mammalian cancer cell lines.

Keywords: Garcinia succifolia, xanthones, benzophenone, triterpenoids

Introduction

Garcinia is the most numerous genus with about 400 species widely distributed in Tropical Asia, Africa, New Caledonia and Polynesia, being widespread throughout the tropical and subtropical regions of the world.1 In Thailand, there are twenty six species of Garcinia having been reported, namely, G. acuminata, G. atroviridis, G. bancana, G. cambogia, G. costata, G. cowa, G. dulcis, G. forbesii, G. fusca, G. garcilis, G. hanburyi, G. hombroniana, G. lanessanii, G. mackeaniana, G. mangostana, G. merguensis, G. nervosa, G. nigrolineata, G. parvifolia, G. rostrata, G. schomburgkiana, G. speciosa, G. succifolia, G. thorelii, G. vilersianaand, and G. xanthochymus.2

The studies of several Garcinia species indicated the presence of a variety of chemical constituents. The genus Garcinia (Guttiferae family) is known as a rich source of polyisoprenylated, benzophenones, xanthones, biflavonoids, triterpenoids and biphenyl derivatives. Several Garcinia species were found to possess a wide range of biological activities such as antimicrobial3, cytotoxic5,7, antitumor9, antimalarial8, antifungal4 and antioxidant5,6activities.

Methodology

The air-dried and finely ground powder from leaves and twigs of Garcinia succifolia were extracted with methanol at room temperature, followed by filtration. The filtrates were combined and evaporated to dryness under reduced pressure to give a crude methanol extract. The extract was evaluated for the cytotoxic activity. The crude methanol extract was dissolved with EtOAc:MeOH (1:1) at room temperature, followed by MeOH. The crude EtOAc:MeOH (1:1) was first separated by column chromatography. Further purification by repeated column chromatography and crystallization afforded macluraxanthone (1), friedelin (2), caloxanthone C (3), lichexanthone (4), stigmasterol (5) and dichromene II (6).

Results and Discussion

The bioactive MeOH:EtOAc (1:1) soluble fraction (see Table 1), obtained from a crude MeOH extract of leaves and twigs of G. succifolia, was separated by column chromatography and recrystallization to yield six known compounds 1-6.

Table 1. Cytotoxic activities of the extract, fractions and pure isolated compounds

aResults are expressed as ED50 (µg/mL): ED50 < 4 µg/mL is considered active for pure compound. *P-388 = Murine lymphocytic leukemia, KB = Human nasopharyngeal carcinoma, HT29 = Human colorectal adenocarcinoma, MCF-7 = Human breast cancer, A549 = Human lung carcinoma, ASK = Cell line from rat glioma, Hek 293= Non-cancerous human embryonic kidney cell line.

Conclusion

Investigation of the MeOH extract of leaves and twigs of Garcinia succifolia has led to the isolation of macluraxanthone (1), friedelin (2), caloxanthone C (3), lichexanthone (4), stigmasterol (5) and dichromene II (6).

Fig1. The structures of compounds 1-6 isolated from leaves and twigs of Garcinia succifolia Kurz.

References:

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Acknowledgement:

This research project is supported by Mahidol University, the Office of the Higher Education Commission and Mahidol University under the National Research Universities Initiative and Center for Innovation in Chemistry (PERCH-CIC).