Curcumin-removed turmeric oleoresin nano-emulsion as a novel botanical fungicide to control anthracnose ( <i>Colletotrichum gloeosporioides</i> ) in litchi
Van Cuong Bui, The Tam Le, Tuyen Hong Nguyen, Phạm Thị Năm, Vũ Đình Hoàng, Xuan Canh Nguyen, Quang De Tran, Thai Hoang, Quang Lê Đăng, Тран Дай Лам
Abstract
Abstract During curcumin production in Vietnam, curcumin-removed turmeric oleoresin (CRTO) has been considered as a by-product. It costs to treat the by-product to prevent environmental pollution. In this study, the by-product was utilized as an active ingredient for preparing a botanical fungicide-based nano-emulsion and evaluated for its in vitro and in vivo control efficacy against Colletotrichum gloeosporioides, a causal agent of anthracnose of litchi, in the laboratory as well as a field trial. The nano-emulsion is colloidally stable and uniform with particle sizes of 95–250 nm. CRTO nano-emulsion significantly affected various Colletotrichum species. Notably, this nano-emulsion showed potent inhibition for the mycelial growth of C. gloeosporioides and solidly suppressed the development of anthracnose on litchi fruits. In the in vitro inhibition test, the equivalent half-maximal inhibitory concentration of CRTO in nano-formulation was 0.11 mg·mL −1 , which was 3.0× and 6.1× lower than IC 50 values of CRTO alone (0.33 mg·mL −1 ) and a mixture of curcuminoids (0.48 mg·mL −1 ), respectively. In the field trial, the litchi anthracnose infection was effectively controlled by nano-formulation. These results suggest that CRTO nano-emulsion could be used as an alternative to harmful synthetic fungicides to control anthracnose on litchi fruits.