A biodegradable device for the controlled release of Piper nigrum (Piperaceae) standardized extract to control Aedes aegypti (Diptera, Culicidae) larvae

Edible Plant Extracts against Aedes aegypti and Validation of a Piper nigrum L. Ethanolic Extract as a Natural Insecticide

The Aedes aegypti mosquito significantly impacts public health, with vector control remaining the most efficient means of reducing the number of arboviral disease cases. This study screened the larvicidal and pupicidal activity of common edible plant extracts. Piper nigrum L. (black pepper) extract production was optimized using accelerated solvent extraction (ASE) and validated following regulatory requirements using HPLC-PDA analytical methodology to quantify its major component-piperine. Larvicidal activity was determined for the standardized P. nigrum fruit ethanol extract (LC₅₀ 1.1 µg/mL) and piperine standard (LC₅₀ 19.0 µg/mL). Furthermore, 9-day residual activity was determined for the extract (4 µg/mL) and piperine (60 µg/mL), with daily piperine quantification. Semi-field trials of solid extract formulations demonstrated 24-day activity against Ae. aegypti larvae. Thus, the standardized P. nigrum extract emerges as a potential candidate for insecticide development to control the arboviral vector.

Polymer-based nanostructures loaded with piperine as a platform to improve the larvicidal activity against Aedes aegypti

Piperine is an alkaloid extracted from the seed of Piper spp., which has demonstrated a larvicidal effect against Ae. aegypti. The incorporation of piperine into nanostructured systems can increase the effectiveness of this natural product in the control of Ae. aegypti larvae. In this study, we evaluated the effectiveness of piperine loaded or not into two nanostructured systems (named NS-A and NS-B) prepared by the nanoprecipitation method. The Ae. aegypti larvae were exposed to different concentrations of piperine loaded or not (2 to 16 ppm) and the mortality was investigated after 24, 48, and 72 hours. The nanostructures prepared were spherical in shape with narrow size distribution and great encapsulation efficiency. The lethal concentration 50 (LC₅₀) for non-loaded piperine were 13.015 ppm (24 hours), 8.098 ppm (48 hours), and 7.248 ppm (72 hours). The LC₅₀ values found for NS-A were 35.378 ppm (24 hours), 12.091 ppm (48 hours), and 8.011 ppm (72 hours), whereas the values found for NS-B were 21.267 ppm (24 hours), 12.091 ppm (48 hours), and 8.011 ppm (72 hours). Collectively, these findings suggested that non-loaded piperine caused higher larval mortality in the first hours of exposure while the nanostructured systems promoted the slow release of piperine and thereby increased the larvicidal activity over time. Therefore, loading piperine into nanostructured systems might be an effective tool to improve the larval control of vector Ae. aegypti.

The impact of different plant extracts on biological parameters of Housefly [Musca domestica (Diptera: Muscidae)]: Implications for management

Housefly is a significant domestic pest, which causes nuisance. The use of insecticides is discouraged to manage housefly; therefore, alternative management strategies are inevitable. The current study investigated the impact of different plant extracts, i.e., Moringa oleifera (moringa), Allium sativum (garlic) and Piper nigrum (black pepper) on biological parameters of house fly. Two different concentrations (i.e., 25 and 50%) of the extracts were blended in larval diet made through mixing of wheat bran, yeast and dried milk powder. The results indicated significant differences for larval duration. Maximum larval duration was recorded for garlic followed by black pepper and moringa, respectively. In case of pupal duration, non-significant differences were observed among plant extracts. Increase rate of oviposition was noticed with moringa at 25% concentration, while decreased oviposition rate was noted for garlic with 50% concentration. Egg hatching percentage remained non-significant for the botanical extracts. The highest survival was observed with moringa, while garlic resulted in the lowest survival. The highest repellency was noticed for garlic followed by black pepper, whereas moringa resulted in the lowest repellency after 30, 60 and 90 min. Prolonged developmental time was observed for bot concentrations of garlic, whereas moringa noted the shortest developmental time. Thus moringa was found to be a promoter of housefly development. Minimum adult emergence was found with both concentrations of garlic followed by 50% concentration of black pepper. The 50% concentration of black pepper promoted the population of adult males, while both concentrations of moringa and 25% concentration of black pepper encouraged the population of female adults. Study outcomes depicted that tested botanical extracts had significant potential for disturbing biological parameters of housefly. The garlic extracts can potentially be used to manage housefly. However, further investigations on the larval and adult mortality are needed.

Piperine: Chemical, biological and nanotechnological applications

Piperine (PIP) is an alkaloid present in several species of piper, mainly Piper nigrum Linn. and P. longum, among other species. The present article provides a comprehensive review of PIP research in the last years concerning its chemical properties, synthesis, absorption, metabolism, bioavailability and toxicity. The reviewed PIP literature has shown many pharmacological properties, such as antidiabetic, antidiarrheal, antioxidant, antibacterial, and anti-parasitic activity of PIP. However, its low solubility and absorption make its application challenging. This review also includes advances in the development of nanosystems containing PIP, including liposomes, micelles, metal nanoparticles, nanofibers, polymeric nanoparticles, and solid-lipid nanoparticles. Finally, we discuss different in vitro and in vivo studies to evaluate the biological activity of this drug, as well as some methods for the synthesis of nanosystems and their physical characteristics.