Biolarvicide activity of extract and essential oil of culantro (Eryngium foetidum L.) on Culex quinquefasciatus larvae in silico and in vitro

Acta Pharmaciae Indonesia: Acta Pharm Indo Winarti et al (2023) Vol 11(2): 8925 https://doi.org/10.20884/1.api.2023.11.2.8925 E-ISSN 2621-4520 Open Access RESEARCH ARTICLE Efficacy of culantro (Eryngium foetidum L.) extract and essential oil as biolarvicides against Culex quinquefasciatus larvae Sri Ayu Winarti, Lela Lailatul Khumaisah , Devi Indah Anwar * ABSTRACT Background: Filariasis, a priority tropical disease in Indonesia, is transmitted by the Culex quinquefasciatus mosquito. The use of conventional synthetic larvicides can lead to environmental and health issues, including poisoning and resistance in target insect populations. Objective: This study explores the utilization of biolarvicides derived from culantro (Eryngium foetidum) to mitigate these adverse effects, focusing on analyzing the components and evaluating the larvicidal efficacy of both the extract and essential oil of E. foetidum. Method: This study employed a molecular docking approach to examine in silico biolarvicidal activity against the odorant binding protein (OBP) receptor and conducted in vitro experiments on Cx. quinquefasciatus larvae using varying concentrations of E. foetidum extract (100, 250, and 500 ppm) and essential oil (10, 50, and 100 ppm). Results: The in silico study identified hynokiflavone and longifenaldehyde as the compounds with the most potent activity, demonstrating binding affinities of -10.2 and -9.5 kcal/mol, respectively. The in vitro assays revealed that the E. foetidum extract achieved 75% larval mortality at an LC50 of 78.59 ppm, while the essential oil resulted in 88% mortality with an LC50 of 10.13 ppm. Conclusion: The extract and essential oil of E. foetidum exhibit significant biolarvicidal activity against Culex quinquefasciatus, offering promising plant-based alternatives to traditional larvicides, with implications for safer and more sustainable vector control strategies. Keywords: Eryngium foetidum, biolarvicidal activity, Culex quinquefasciatus, natural insecticides, vector control Introduction Indonesia’s tropical climate contributes to its status as a hotspot for infectious diseases transmitted by bacteria, viruses, and parasites [1]. Among these, filariasis—primarily spread by the Cx quinquefasciatus mosquito—poses a significant health concern [2]. The Indonesian Ministry of Health reported 8,365 filariasis cases in 2022 [2]. In combating this disease, the government has initiated mass drug administration strategies, which include synthetic larvicides for Department of Chemistry, Faculty of Science and Technology, Universitas Muhammadiyah Sukabumi, Sukabumi 43113, West Java, Indonesia *Corresponding author: Jl. R. Syamsudin S.H. No. 50 Telp. (0266) 218345 Sukabumi 43113. Email: mosquito control. However, these measures face challenges such as potential toxicity, environmental pollution, and the development of insect resistance [3], prompting interest in safer and eco-friendly alternatives, such as plant-based biolarvicides. Research has identified several plants with biolarvicidal properties against Cx. quinquefasciatus larvae, including betel leaves [4], vetiver [5], and grapefruit leaves [6]. Notably, culantro (Eryngium foetidum L.) emerges as a promising candidate due to its wide-ranging bioactivities, such as antibacterial, antioxidant, antifungal, antilarval, and antidiabetic properties [7]. The larvicidal efficacy of E. foetidum has been demonstrated in studies showing its essential oil’s potency against Aedes albopictus larvae, with an LC50 of 33.3 ppm [8]. Copyright © The Author(s) 2023. This article is distributed under a Creative Commons Attribution 4.0 International License 1 Winarti et al (2023) This study aims to further explore E. foetidum’s potential by analyzing its components and evaluating the efficacy of its extract and essential oil as biolarvicides against Cx. quinquefasciatus larvae. It employed both in vitro methods and in silico molecular docking to investigate the interactions with odorant binding protein (OBP) receptors, which are critical for insect olfaction. This dual approach seeks to identify the most effective larvicidal compounds and understand their mechanisms, contributing to the development of safer and more sustainable mosquito control strategies. Efficacy of culantro (Eryngium foetidum L.) extract and essential oil Phytochemical screening of sample extract Phytochemical screening was conducted to detect the presence of various compounds, including flavonoids, alkaloids, saponins, tannins, terpenoids, triterpenoids, steroids, phenolics, and glycosides [11,12]. Flavonoids: A mixture of 1 mL of the extract, 1 gram of magnesium powder, and 1 mL of concentrated HCl was prepared in a test tube. The appearance of a red, yellow, or orange indicated a positive test for flavonoids. Method Materials Alkaloids: 1 mL of the extract was combined with a few drops of 1% HCl in a test tube. After the solution dissolved, 1 mL of Mayer’s reagent was added. The formation of a white precipitate or a cloudy solution indicated the presence of alkaloids. The larvicidal activity was assessed on Cx. quinquefasciatus instar III larvae, obtained from Lokalitbang Kesehatan Pangandaran, West Java, Indonesia. Saponins: 10 mL of distilled water was added to 1 mL of the extract and shaken for 10 seconds. Persistent foam formation after 10 minutes suggested the presence of saponins. Plant material The aerial parts of the E. foetidum plant were collected from Pasawahan, Takokak District, Cianjur Regency, West Java, Indonesia. The plant material was authenticated at the Biology Laboratory of Universitas Muhammadiyah Sukabumi. Extraction The E. foetidum was cleaned, air-dried, and then ground into a powder. Using the maceration method, one kilogram of this powdered sample was extracted with methanol as the solvent over a period of 72 hours. The mixture was then filtered through a Buchner funnel, and the filtrate was concentrated under reduced pressure at 50°C using a rotary vacuum evaporator. Distillation For this process, 14.8 kilograms of the E. foetidum samples underwent water and steam distillation. The plant material was placed in a distillation kettle, which was filled with water and separated from the plant material by a perforated filter. This setup allowed the steam to permeate the plant material and then travel through a connecting pipe to a condenser. In the condenser, the steam reverted to liquid, allowing the collection of the essential oil as it dripped from the end of the pipe into a designated container [10]. Acta Pharmaciae Indonesia: Acta Pharm Indo 11(2): 8925 https://doi.org/10.20884/1.api.2023.11.2.8925 Tannins: A mixture of 1 mL of the extract and 5 mL of distilled water was treated with a few drops of 5% FeCl3 solution. A dark green or bluish-green color change indicated the presence of tannins. Terpenoids: A test tube containing 2 mL of CHCl3, 2 mL of the extract, and 3 mL of concentrated H2SO4 was (...truncated)