Searching for bioactive natural products from ginger rhizomes (Zingiber officinale)

Name: Kanta Keosaeng

LCSH: Kasetsart University -- Dissertations. Ph.D. (Chemistry) 2021

Classification :.LCCS: QK495.Z65

LCSH: Kasetsart University. -- Department of Chemistry -- Dissertations

LCSH: Ginger

LCSH: Plant extracts

LCSH: Bioactive compounds

LCSH: Insecticides

LCSH: Plant bioactive compounds

Abstract: The rise in the number of the use of botanical origin products in several industries has attracted continuing interest in the discovery of bioactive natural products and their biological activities. This present work focused on exploring the insecticidal secondary metabolites present in ginger (Zingiber officinale) rhizomes against Spodoptera species. Four sequential extracts were evaluated against second instars of the most destructive Spodoptera spp. (Spodoptera litura, Spodoptera exigua, and Spodoptera frugiperda) by topical application. The results revealed that the hexane extract was the most potent to S. exigua with the LD50 of 9.92 and 8.40 µg/larva at 24 and 48 h posttreatment, respectively, followed by S. frugiperda with LD50 of 18.98 and 13.27 µg/larva at 24 and 48 h posttreatment, respectively, whereas this extract was inactive against S. litura. Subsequently, six known phenolic ketones were isolated from the most active hexane extract identified as 6-, 8-, 10- gingerols and 6-, 8-, 10- shogaols. Interestingly, comparative toxicity of the isolated gingerols and shogaols against two most susceptible insects concluded that shogaols were significantly more toxic to S. frugiperda and S. exigua than gingerols. In particular, 8-shogaol was the first identified as the most active ingredient against S. frugiperda with the LD50 of 7.68 and 3.96 µg/larva at 24 and 48 h posttreatment, respectively. Meanwhile, the hexane extract of Z. officinale was applied as binary mixtures with the most active ethyl acetate extract of Alpinia galanga rhizomes, which resulted in antagonistic interactions against S. exigua. Moreover, an additional study has been successfully made to enhance the toxicity against S. exigua by structurally modifying of thymol to thymyl esters (8- 14). Among them, thymyl butanoate (9) was the most toxic to S. exigua with LD50 of 2.33 and 1.62 µg/larva at 24 and 48 h posttreatment, being about > 15.5 times more active than the parent thymol (7). Additionally, the methanol extract from Z.officinale rhizomes exhibited moderate AChE inhibitory activity with IC50 = 393.55 µg/mL, being the most effective compared to the other extracts including the hexane extract.

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Wanchai Pluempanupat

Role: Thesis Advisor

Name: Pakorn Wattana-Amorn

Role: Thesis CO-Advisor

Name: Pitak Chuawong

Role: Thesis CO-Advisor

Created: 2021

Modified: 2025-07-26

Issued: 2025-07-26

วิทยานิพนธ์/Thesis

application/pdf

URL: https://www.lib.ku.ac.th/KUthesis/2564/kanta-keo-all.pdf

CallNumber: QK495.Z65 .K36

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degraee

Descipline: Chemistry

Grantor: Kasetsart University

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