Rotundial, a New Natural Mosquito Repellent from the Leaves ofVitex rotundifolia

Abstract

A new natural mosquito repellent was isolated from fresh leaves of Vitex rotundifolia. Its structure was elucidated by an extensive NMR spectral analysis to be a cyclopentene dialdehyde named rotundial. This compound possessed potent repelling activity against Aedes aegypti.

Monoterpene Constituents from Cistanche tubulosa-Chemical Structures of Kankanosides A-E and Kankanol-

“…25) Kankanoside A ( Enzymatic Hydrolysis of 1, 4, and 6 with b b-Glucosidase A solution of 1 (7.7 mg) in H 2 O (1.5 ml) was treated with b-glucosidase (5.0 mg, from almond, Oriental Yeast Co., Tokyo, Japan) and the solution was stirred at 37°C for 3 d. After EtOH was added to the reaction mixture, the solvent was removed under reduced pressure and the residue was purified by HPLC [MeOH-H 2 O (55 : 45, v/v)] to furnish kankagenin a (1a, 2.3 mg, 56%). Through a similar procedure, (R)-rotundiol 33,34) (4a, 1.2 mg, 69%) and (2E,6R)-8-hydroxy-2,6-dimethyl-2-octenoic acid 36) (6a, 6.8 mg, 62%) were obtained from 4 (3.5 mg) and 6 (20.4 …”

Comparison of the tick repellent efficacy of chemical and biological products originating from Europe and the USA

“…Among the isolated substances, the following were found often at high concentrations: citronellol, geraniol, cineoles, monoterpenoids, cyclopantenes, azadirachtin etc. (Büchel 1970;Cockcroft et al 1998;Mumcuoglu et al 1996;Thorsell 1998;Marazanye et al 1988;Watanabe et al 1995;Sharma et al 1993Sharma et al , 2001Schreck et al 1995). However, in many cases, it turned out that the essential oils alone-especially in high concentrations-may introduce phototoxic and allergenic reactions or even lead to olfactory and skin reactions (see Barnard 1999;Faulde 2001;Semmler et al 2009).…”

Evaluation of leaf extracts of Vitex negundo L. (Family: Verbenaceae) against larvae of Culex tritaeniorhynchus and repellent activity on adult vector mosquitoes

“…Its structure was elucidated by an extensive nuclear magnetic resonance spectral analysis to be a cyclopentene dialdehyde named rotundial. This compound possessed potent repelling activity against Aedes aegypti (Watanabe et al 1995). The repellent efficacy of leaf extract of V. negundo is also comparable with CO 2 extract of the seeds of the Mediterranean plant Vitex agnus castus (monks pepper; Mehlhorn et al 2005).…”