Excito-repellency Activity of Andrographis paniculata (Lamiales: Acanthaceae) Against Colonized Mosquitoes

Abstract

Excito-repellency activity of plant extracts have been increasingly studied as mosquito repellents. In this study, the crude extract of Andrographis paniculata was evaluated for its noncontact repellency, contact excitation (irritancy + repellency), and knockdown/toxicity response against five colonized mosquitoes; Aedes aegypti (L.), Aedes albopictus (Skuse), Anopheles dirus Peyton & Harrison, Anopheles epiroticus Linton & Harbach, and Culex quinquefasciatus Say (Diptera: Culicidae) using an excito-repellency assay system under laboratory-controlled conditions. The escape responses were observed at four different concentrations (0.5–5.0% w/v) with A. paniculata showing strong spatial repellency against Ae. albopictus (96.7% escape) and Ae. aegypti (71.7% escape) at the 2.5% and 0.5% concentrations, respectively. At 0.5% and 5.0% concentrations, the greatest repellency was seen for An. dirus (48.2% escape) and Cx. quinquefasciatus (59.7% escape), respectively. Comparatively, low repellency action was observed against An. epiroticus (1.6–15.0% escape). Escape in contact assays (before adjustment) was generally less pronounced compared to noncontact spatial repellency, with Ae. albopictus showing highest percent escape (71.4% escape) in the contact assay at 1.0% concentration. After adjusting for spatial repellency, escape due to contact irritancy alone was either not present or an insignificant contribution to the overall avoidance response for all species. No knockdown or mortality at 24-h postexposure was observed in any trials. These findings indicate that the A. paniculata crude extract is more active against day-biting mosquitoes; however, this may be a reflection of the time of testing. This study demonstrates compelling evidence that A. paniculata extract performs primarily as a spatial repellent. Further investigations exploring the use A. paniculata as a potential active ingredient in repellent products are needed.

Behavioral responses to transfluthrin by Aedes aegypti, Anopheles minimus, Anopheles harrisoni, and Anopheles dirus (Diptera: Culicidae)

“…The three primary modes of action of a chemical are insecticidal (killing) and two behavioral responses, either by contact locomotor excitation ('irritancy') and/or noncontact spatial repellency [26]. The excito-repellency (ER) assay system is a well-established behavioral testing system to evaluate sublethal chemical actions such as contact excitation and noncontact repellency of synthetic and natural-derived compounds [27][28][29][30][31][32][33][34][35][36]. By measuring flight movement, i.e.…”

Excito-repellency of Myristica fragrans Houtt. and Curcuma longa L. extracts from Southern Thailand against Aedes aegypti (L.)

“…aegypti , even at the highest concentration (5.0% w/v = 50,000 ppm), when exposed to treated-filter paper inside the ER chamber. It has been previously suggested that mosquitoes can avoid collectively lethal doses at exposures of only 30 min or less (if they escaped) in a larger space within the ER chamber (33.5 × 22.5 × 22.5 cm) ( Sukkanon et al, 2020 ). One limitation of this study is that the ER chambers were made of window-less stainless steels; therefore, we were unable to observe and confirm mosquito movement inside each chamber during the exposure period.…”

“…albopictus and Ae. aegypti at high concentrations (2.5%–5.0% w/v; Sukkanon et al, 2020 ). Contrarily, contact irritancy and non-contact repellency are the primary and secondary actions, respectively, of Cananga odorata oil and are mainly used against the night-biting mosquitoes An.…”

Chinese herbal medicine: Fighting SARS-CoV-2 infection on all fronts

“…4 A) ( Kumar et al, 2019 ). Recent studies have reported numerous pharmacological properties of Herba andrographitis extracts, both in vitro and in vivo , against HIV (EC 50 value of 5.49 μg/mL) ( Feng et al, 2012 ), complement (EC 50 value of 23.1–638.3 μg/mL) ( Wen et al, 2020 ), and excito-repellency (96.7% escape at 0.5–5.0% w/v concentration) ( Sukkanon et al, 2019 ). This agent has also been used to treat osteoarthritis in the knee; a 300 mg/day dose was effective and safe when applied to reduce pain ( Hancke et al, 2019 ).…”