Rhinacanthin production by four hairy root lines of Rhinacanthus nasutus (L.) Kurz

Rhinacanthus nasutus (L.) Kurz is a medicinal plant used in Southeast Asia for treatment of several skin diseases [1]. The plant extract possessed several pharmacological activities such as antifungal and antiviral activities [2]. The naphthoquinone compounds, namely rhinacanthins, are major chemical constituents in this plant. In this study, technique of hairy roots induction by Agrobacterium rhizogenes was used for increasing the rhinacanthin level. Four hairy root lines of R. nasutus, including HR11325, HR13332, HR13333 and HR15834, were induced on the leaf explants by A. rhizogenes strains ATCC 11325, 13332, 13333 and 15834, respectively. Transformation percentages were 55%, 25%, 70% and 60%, respectively. The fragments of rolB and rolC genes were observed in all hairy root lines using PCR technique indicating the successful integration of the T-DNA fragment of Ri plasmid of A. rhizogenes to the genome of the hairy roots. Rhinacanthin production from these hairy roots was determined using HPLC technique. HR11325 produced rhinacanthin-C as a major compound together with rhinacanthin-D, and -N with the yields of 2.163, 0.042 and 0.006% w/w, respectively. In contrast, HR13332, HR13333 and HR15384 contained only rhinacanthin-C and -D. The amount of rhinacanthin-C in these three hairy roots were 0.843, 0.824, and 1.148% w/w, while those of rhinacanthin-D were 0.039, 0.012 and 0.017% w/w, respectively.

Acknowledgements: National Research Council of Thailand (NRCT), Prince of Songkla University

References: [1] Farnswort, N.R. et al. (1992) Thai Medicinal Plants: Plant Recommended for Primary Health Care System. Prachachon. Bangkok.

[2] Wu, T.S. et al. (1998) Chem. Pharm. Bull. 46:413–418.