INCREASED RHINACANTHIN PRODUCTION IN RHINACANTHUS NASUTUS HYDROPONICS BY DUAL ELICITATION USING CHITOSAN AND TRICHODERMA HARZIANUM

Increased rhinacanthin production by dual elicitations

Abstract

A highly efficient hydroponic cultivation system was developed to enhance rhinacanthin production in Rhinacanthus nasutus. Within this framework, dual elicitation using chitosan (CHI) and Trichoderma harzianum extract (THE) was identified as a promising technique, strategically employed to increase the overall yield of rhinacanthins. R. nasutus hydroponics were treated with CHI (0.15 mg ml^-1) and THE (1.0 mg ml^-1) either simultaneously or sequentially, with elicitor exposure periods ranging from 24 to 96 h. The total rhinacanthin content (rhinacanthin-C, -D, and -N) in roots and leaves was analyzed using HPLC. Simultaneous dual elicitation with CHI and THE resulted in lower rhinacanthin levels in both leaves and roots compared to single elicitation with either agent. Among the treatments, the highest rhinacanthin contents in the leaves (7.05% w/w) and roots (9.65% w/w) were observed with sequential dual elicitation, in which 0.15 mg ml^-1 CHI was applied for 48 h, followed by 1.0 mg ml^-1THE for 24 h and 72 h, respectively. In contrast, a reversed sequential dual elicitation, in which 1.0 mg ml^-1 THE was applied for 24 h followed by 0.15 mg ml^-1 CHI for 72 h and 48 h resulted in rhinacanthin contents of 7.34% and 7.32% w/w in the leaves and roots, respectively. The present study demonstrates an effective approach for enhancing rhinacanthin content in hydroponically cultivated R. nasutus through sequential dual elicitation using CHI and THE.