Impact of composted guava leaves and neem seeds on the growth and curcuminoid- and xanthorrhizol-yields of Curcuma zanthorrhiza RoxB

The compost from the waste of pharmaceutical industries, such as guava leaves (GL) and neem seeds (NS) is used in organic agriculture. Curcuma zanthorrhiza RoxB. is a widely recognized herbal medicine that grows natively in Indonesia. Curcuminoids and xanthorrhizol are the primary bioactive components of C. zanthorrhiza. In this study, we aimed to evaluate the impact of GL and NS compost on the growth and bioactive yields of C. zanthorrhiza. Treatments consisted of cow manure, GL compost, NS compost, GL+NS compost, or a no compost control, at 2 and 4 kg per plant. Results demonstrated that the NS and GL+NS compost applied with 4 kg per plant had increased fresh rhizome yield compared with the other treatments. Composted NS at 2 kg per plant increased the plant height and pseudo stem diameter traits compared with the control treatment. The compost application of GL+NS at 2 and 4 kg per plant significantly increased the leaf length and number of shoots. All treatments showed unchanged the leaf width and number of leaves. The compost application of GL and NS (2 kg per plant) showed higher production of curcuminoidsthan the control. The compost consisting of GL (2 kg per plant), NS (4 kg per plant), and GL+NS also increased the production of xanthorrhizol compared with the control treatment. Results illustrated the practical application of GL and NS composts from industrial pharmaceutical extraction waste for the organic farming cultivation of C. zanthorrhiza.