Larvicidal efficacy of Ethiopian ethnomedicinal plant Juniperus procera essential oil against Afrotropical malaria vector Anopheles arabiensis (Diptera: Culicidae)

Casearia tomentosa fruit extracts exposed larvicidal activity and morphological alterations in Culex quinquefasciatus and Aedes albopictus under in vitro and semi field conditions

Mosquitoes are notorious insects that transmit a wide range of infectious diseases, including zika, malaria, chikungunya, filariasis, and dengue. The overuse and incorrect application of synthetic pesticides to control mosquitoes has resulted in resistance development and environmental contamination, both of which have had a negative impact on human health. To address this issue, the larvicidal and pupicidal potential of acetone extract from Casearia tomentosa fruits was investigated. The extract was evaluated in a lab setting against all larval instars and pupa of Culex quinquefasciatus and Aedes albopictus, as well as against third instar larvae in a semi-field condition. Purified compounds through TLC were also tested against 3rd instar larvae of both mosquito and non-target organisms. The FT-IR and GC-MS analyses were used to characterise the extract. Morphological aberration caused by the acetone extract was observed using FESEM. The anal gills and respiratory siphon of both mosquitoes showed significant deformation from their normal state. 100 ppm was found to cause 100% larval mortality at 24 h of exposure in case of Cx. quinquefasciatus and at 72 h of exposure in Ae. albopictus larvae. After 72 h of exposure under in vitro conditions, the extract demonstrated considerable larvicidal activity with LC50 values of 38.33 and 47.56 against 3rd instar larvae of Culex quinquefasciatus and Aedes albopictus, respectively. The acetone extract can be considered as a highly effective mosquito larvicidal agent that is safe for the environment.

Octadecadienoate derivatives from Michelia champaca seed extract as potential larvicide and pupicide against Dengue vector Aedes albopictus

The present study was designed aiming at finding novel botanicals for controlling the vector population. Objective was to evaluate the larvicidal and pupicidal efficacies of crude and solvent extracts of Michelia champaca seed against the notorious dengue vector Aedes albopictus. 0.5% concentration of the crude extractive and 40 ppm concentration of ethyl acetate extractive were enough to execute 100% of larval mortality of all the instars after 72 h of exposure and the LC50 and LC90values (95% confidence level) of ethyl acetate extractive were 0.9880 ppm and 36.0491 ppm. In case of pupicidal bioassay, 100% mortality was observed at 200 ppm of ethyl acetate extract. Through TLC techniques, the bioactive compounds were isolated, which caused remarkable larval toxicity at 15 ppm concentration. Three-way factorial ANOVA analysis showed different concentrations, time intervals, and instars revealed a significant difference in larval death. FT-IR analysis revealed the presence several important functional groups. Presence of methyl 5,12-octadecadienoate and ethyl 9cis,11trans-octadecadienoate were ascertained by GC-MS analysis. The said bioactive compounds showed very low toxicity in non-target organisms such as damselfly (Ischnura sp.) and water bug (Diplonychus sp.) Thus, proclaiming the potentialities of Michelia champaca seed extracts as larvicidal and pupicidal agents against Ae. albopictus.

Evaluation of the Anti-Malarial Activity of the Crude Root Extract and Solvent Fraction of Sesamum indicum (Fabaceae)

Background

A major cumbersome factor in malaria control measure is the new coming antimalarial drug resistance strains. The increase of resistance to the available marketed antimalarial agents dictates the scientific community to search new alternative antimalarial agent from traditional plants. Therefore, our study assesses the antimalarial activity of the crude root extract and solvent fraction of Sesamum indicum in mice.

Methods

The roots of Sesamum indicum were extracted by 80% methanol and fractionated using three solvents with different polarities. The in vivo antimalarial activity was assessed at 200 mg/kg, 400 mg/kg, and 600 mg/kg of the root crude extract and solvent fraction using the 4-day suppressive test. Similarly, the n- butanol fraction extract, which showed better suppression potential in 4-day suppressive test from other fractions was also evaluated in the curative model to assess its curative potential. The % parasitemia suppression, mean survival time, body weight change, rectal temperature change, and packed cell volume change were also evaluated in both models.

Results

Our finding revealed that the crude extract and solvent fraction treated groups had a statistical significant parasitemia suppression and mean survival time improvement as compared to the negative control (p<0.001) in both models in a dose-dependent fashion. The higher dose n-butanol fraction treated group (600mg/kg) showed the highest suppression effect and mean survival time prolongation in both tests from the other two fractions. However, the lowest suppressive effect was observed in 200 mg/kg aqueous fraction extract-treated groups in the 4-day suppressive test.

Conclusion

The crude root extract and solvent fractions of Sesamum indicum possessed a dose dependent antimalarial activity and a significant change in other parameters in both models that strengthen the traditional claim.

Potential Anticancer Activity of Juniperus procera and Molecular Docking Models of Active Proteins in Cancer Cells

Medicinal plants provide a wide range of active compounds that can be exploited to create novel medicines with minimal side effects. The current study aimed to identify the anticancer properties of Juniperus procera (J. procera) leaves. Here, we demonstrate that J. procera leaves' methanolic extract suppresses cancer cells in colon (HCT₁₁₆), liver (HepG2), breast (MCF-7), and erythroid (JK-1) cell lines. By applying GC/MS, we were able to determine the components of the J. procera extract that might contribute to cytotoxicity. Molecular docking modules were created that used active components against cyclin-dependent kinase 5 (Cdk5) in colon cancer, aromatase cytochrome P450 in the breast cancer receptor protein, the -N terminal domain in the erythroid cancer receptor of the erythroid spectrin, and topoisomerase in liver cancer. The results demonstrate that, out of the 12 bioactive compounds generated by GC/MS analysis, the active ingredient 2-imino-6-nitro-2H-1-benzopyran-3-carbothiamide proved to be the best-docked chemical with the chosen proteins impacted by DNA conformational changes, cell membrane integrity, and proliferation in molecular docking studies. Notably, we uncovered the capacity of J. procera to induce apoptosis and inhibit cell growth in the HCT₁₁₆ cell line. Collectively, our data propose that J. procera leaves' methanolic extract has an anticancer role with the potential to guide future mechanistic studies.

Anti-mosquito properties of Pelargonium roseum (Geraniaceae) and Juniperus virginiana (Cupressaceae) essential oils against dominant malaria vectors in Africa

Background

More than 90% of malaria cases occur in Africa where the disease is transmitted by Anopheles gambiae and Anopheles arabiensis. This study evaluated the anti-mosquito properties of Juniperus virginiana (JVO) and Pelargonium roseum (PRO) essential oils (EOs) against larvae and adults of An. gambiae sensu lato (s.l.) from East Africa in laboratory and semi-field conditions.

Methods

EOs was extracted from the aerial green parts of Asian herbs by hydrodistillation. Their constituents were characterized by gas chromatography-mass spectrometry (GC-MS). Larvicidal activities of JVO, PRO, and PRO components [citronellol (CO), linalool (LO), and geraniol (GO)] were investigated against An. gambiae sensu stricto (s.s.). The percentage of knockdown effects and mortality rates of all oils were also evaluated in the adults of susceptible An. gambiae s.s. and permethrin-resistant An. arabiensis.

Results

GC-MS analyses identified major constituents of JVO (sabinene, dl-limonene, β-myrcene, bornyl acetate, and terpinen-4-ol) and PRO (citronellol, citronellyl formate, L-menthone, linalool, and geraniol). Oils showed higher larvicidal activity in the laboratory than semi-field trials. The LC₅₀ values for JVO/PRO were computed as 10.82–2.89/7.13–0.9 ppm and 10.75–9.06/13.63–8.98 ppm in laboratory and semi-field environments, respectively at exposure time of 24–72 h. The percentage of knockdown effects of the oils were also greater in An. gambiae s.s. than in An. arabiensis. Filter papers impregnated with JVO (100 ppm) and PRO (25 ppm) displayed 100% mortality rates for An. gambiae s.s. and 3.75% and 90% mortality rates, for An. arabiensis populations, respectively. Each component of CO, LO, and GO exhibited 98.13%, 97.81%, and 87.5%, respectively, and a mixture of the PRO components indicated 94.69% adult mortality to permethrin-resistant An. arabiensis.

Conclusions

The findings of this study show that PRO and its main constituents, compared to JVO, have higher anti-mosquito properties in terms of larvicidal, knockdown, and mortality when applied against susceptible laboratory and resistant wild populations of An. gambiae s.l. Consequently, these oils have the potential for the development of new, efficient, safe, and affordable agents for mosquito control.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04220-8.

Antimalarial Activity of Seed Extracts of Schinus molle Against Plasmodium berghei in Mice

Background.

Malaria is a major public health problem in developing countries. In Ethiopian, the seeds of Schinus molle are used for the management of malaria. Therefore, the current study aimed to evaluate in vivo antimalarial activity of hydro-alcoholic crude extract and solvent fractions of Schinus molle seeds in Plasmodium berghei infected mice.

Methods.

An 80 percent of methanolic crude extract and solvent fractions of Schinus molle seeds were tested for antimalarial activity at 100, 200 and 400 mg/kg doses. The parasitemia level, packed cell volume, body weight, survival of date and rectal temperature were used to evaluate the anti-malarial activity of the extracts. One-way ANOVA followed by post hoc Tukey’s HSD multiple comparison test was employed and the result was expressed in mean ± SEM (standard error of the mean).

Results.

The curative activity of the highest dose of crude extract and aqueous fraction of Schinus molle seeds was 69.86% and 73.82% (p < 0.001), respectively. In the prophylactic test, aqueous fraction had 72.39% (p < 0.001) suppression antimalarial activity. Among solvent fractions, only chloroform fraction was significantly attenuated packed cell volume reduction. The mice treated with crude extract and aqueous fraction had longer survival date than vehicle-treated mice (p < 0.001).

Conclusion.

The experiment finding showed that the crude extract and solvent fractions of Schinus molle seeds had significant curative and prophylaxis anti-plasmodial activity. This result revealed that the Schinus molle seeds extract has promising antimalarial activity against Plasmodium berghei. However, further confirmatory studies, isolation and characterization of the active constituents are recommended.

Antimalarial Activity of Fagaropsis angolensis (Rutaceae) Crude Extracts and Solvent Fractions of Its Stem Bark Against Plasmodium berghei in Mice

BACKGROUND

A current challenge in malaria control and elimination is the progressive resistance to most antimalarial drugs which necessitates the discovery of new options. Hence, the current study was initiated to investigate the antimalarial activity of the stem bark of Fagaropsis angolensis in mice.

METHODS

The test material was extracted using 80% methanol in a cold maceration technique and further fractionated in solvents of varied polarity. Acute oral toxicity was assessed following the OECD guideline no. 425 protocol. Then, the antimalarial activities of the crude extract and the fractions were evaluated in a 4-day suppression test. Rane's test was also used to evaluate the curative potential of the n-butanol fraction that showed the highest effect during the 4-day suppressive test. Parameters such as parasitemia suppression, mean survival time, packed cell volume, rectal temperature, and body weight were determined to establish the activity.

RESULTS

The acute oral toxicity test indicated that the plant did not cause any signs of behavioral changes or mortality at 200 mg/kg limit dose. In a 4-day suppression test, a significant dose-dependent reduction in the parasitemia level and prolongation of survival time were observed (p<0.001) in all three doses of the crude extract compared with the negative control. The crude extract also exhibited a significant (p<0.001) protective effect in packed cell volume and rectal temperature decline in all three doses in a dose-dependent fashion compared with the negative control. Among all fractions, the n-butanol fraction displayed the highest effects in all parameters in the 4-day suppression test. In addition, the n-butanol fraction also showed a significant percentage of parasitemia suppression effects at all doses in Rane's test. Furthermore, higher free radical scavenging activity was observed in the n-butanol fraction and the 80% methanol extract.

CONCLUSION

This study established that Fagaropsis angolensis had shown potential antimalarial activity as evidenced by the significant effects in the different parameters, upholding its traditional use for the treatment of malaria and laying the foundation for further investigations.

Rutin as a Promising Inhibitor of Main Protease and Other Protein Targets of COVID-19: In Silico Study

The process of investigating a possible cure for coronavirus disease 2019 (COVID-19) in vitro and in vivo may take a long time. For this reason, several in silico studies were performed in order to produce preliminary results that could lead to treatment. Extract of Juniperus procera Hochst is used as a traditional medicine for recovery from flu in Saudi Arabia. In the present study, more than 51 phytochemicals of J. procera were docked against the main protease of COVID-19. Rutin gave the highest interaction score among all the phytochemicals and the commercially available antiviral drugs. Lopinavir showed the second highest binding score. Rutin and lopinavir were further investigated using homology models of COVID-19. Rutin showed a better inhibition score in 9 of the 11 of homology models compared with lopinavir. Analysis of ligand-protein interaction contacts revealed that 3 residues (Glu166, Gly143, and Thr45) of the main protease formed hydrogen bonds with rutin. This simulation study suggests that rutin could be a possible effective inhibitor of several COVID-19 protein targets, including the main protease. Rutin, already available for commercial use, was evaluated for its ability as a possible drug. To our knowledge, this is the first study that suggests rutin having a possible strong inhibitory role against several protein targets of COVID-19.

Plant-Derived Essential Oils; Their Larvicidal Properties and Potential Application for Control of Mosquito-Borne Diseases

Mosquito-borne diseases are currently considered as important threats to human health in subtropical and tropical regions. Resistance to synthetic larvicides in different species of mosquitoes, as well as environmental pollution, are the most common adverse effects of excessive use of such agents. Plant-derived essential oils (EOs) with various chemical entities have a lower chance of developing resistance. So far, no proper classification based on lethal concentration at 50% (LC₅₀) has been made for the larvicidal activity of EOs against different species of Aedes, Anopheles and Culex mosquitoes. To better understand the problem, a summary of the most common mosquito-borne diseases have been made. Related articles were gathered, and required information such as scientific name, used part(s) of plant, target species and LC₅₀ values were extracted. 411 LC₅₀ values were found about the larvicidal activity of EOs against different species of mosquitoes. Depending on the obtained results in each species, LC₅₀ values were summarized as follows: 24 EOs with LC₅₀ < 10 µg/mL, 149 EOs with LC₅₀ in range of 10- 50 µg/mL, 143 EOs having LC₅₀ within 50- 100 µg/mL and 95 EOs showing LC₅₀ > 100 µg/mL. EOs of Callitris glaucophylla and Piper betle against Ae. aegypti, Tagetes minuta against An. gambiae, and Cananga odorata against Cx. quinquefasciatus and An. dirus having LC₅₀ of ~ 1 µg/mL were potentially comparable to synthetic larvicides. It appears that these plants could be considered as candidates for botanical larvicides.