Bedbugs are blood-feeding arthropods that cause anemia in humans upon heavy feeding. Control measures are unsuccessful due to resistance to development, environmental pollution, and cost. There is a need to explore natural herbal-based phytochemicals to combat bedbugs. In this study, compounds from Comiphora africana resin were sequentially extracted, fractionated, identified, and evaluated against bedbugs as individual compounds and in combinations. The chemical constituents of the most active fraction were identified using Gas Chromatography-Mass Spectrometry. Results showed that the dichloromethane crude extract had the highest mean repellency (98.5% with an LC50 of 4.96 mg/L after 24 and 72 h of exposure time, respectively), similar to the positive control (neocidol). Column chromatographic separation of the dichloromethane extract yielded 9 fractions where “FR7” (eluted with 60% n-hexane in ethyl acetate) demonstrated the highest mean repellency of 79.0% with an LC50 of 10.12 mg/L after 2 and 24 h exposure times, respectively. From the identified compounds of FR7, cedrol had significantly ( P < .05) higher mean repellency (80.5%) after 6 h of exposure and toxicity (27.43 mg/L) after 24 h exposure. A six-constituent blend of compounds from FR7 [9-octadecenoic acid-ethyl-ester, octadecadien-1-ol, citronellyl formate, cedrol, n-hexadecanoic acid, (1,2)-dihydro-6-methoxy-naphthalene] had the highest mean repellency (93.4% after 12 h exposure) and toxicity (8.83 mg/L after 72 h exposure) than the other blends and individual compounds. This study reports fractions/compounds that can be used in bedbug control measures.

Bedbugs (Cimex lecturalius Linnaeus) are ecto-parasite pests that wholly feed on human and domestic animals’ blood causing anemia to the host on excessive feeding. Bedbug control has proved futile due to various challenges including; development of insecticide resistance, high associated cost and environmental pollution. Natural herbal-based phytochemicals remain unexploited and we focused on Comiphora africana (A. Rich.) Engl. resin traditsionally used bedbug control. We previously showed that dichloromethane extract of C. africana resin is highly repellent and toxic against bedbugs. In this study, we isolated compounds from the dichloromethane extract using column chromatographic techniques. The isolated compounds were evaluated for repellency and toxicity against bedbugs; and characterized using conventional spectroscopic techniques. Five compounds (taraxasterol, pseudo-taraxasterol, beta-sitosterol, fungisterol and guggusterol) were isolated and characterized for the first time in this plant. Fungisterol had the highest repellency (75%) against bedbugs which was not significantly different (P > .05) to the positive control (neocidol) (74%) after > one-hour exposure. Fungisterol also elicited highest toxicity against bedbugs with LC50 of 25.73 mg/L after 24 h exposure. Blending fungisterol with other identified active terpenes did not synergize the overall repellent/toxic responses. This study identifies active compounds in C. africana resin and therefore lays a solid background in bedbug control using isolated compounds.