Synergistic Effects of Plant Growth Regulators and Elicitors on α-Humulene and Zerumbone Production in Zingiber zerumbet Smith Adventitious Root Cultures

Abstract

Zingiber zerumbet, also known as ‘Lempoyang’, possesses various phytomedicinal properties, such as anticancer, antimicrobial, anti-inflammatory, antiulcer, and antioxidant properties. Secondary metabolites possessing such properties i.e., zerumbone and α-humulene, are found dominantly in the plant rhizome. Synergistic effects of plant growth hormones and elicitors on in vitro α-humulene and zerumbone production, and biomass growth, in adventitious root culture (AdRC) of Z. zerumbet cultivated in a two-stage culture are reported. The culture was induced by supplementation of 1.0 mg/L NAA and 2.0 mg/L IBA (dark), and subsequently maintained in medium supplemented with 1 mg/L NAA and 3 mg/L BAP (16:08 light-dark cycle), yielded the production of zerumbone at 3440 ± 168 µg/g and α-humulene at 3759 ± 798 µg/g. Synergistic elicitation by 400 μM methyl jasmonate (MeJa) and 400 μM salicylic acid (SA) resulted in a 13-fold increase in zerumbone (43,000 ± 200 µg/g), while 400 μM MeJa and 600 μM SA produced a 4.3-fold increase in α-humulene (15,800 ± 5100 µg/g) compared to control.