Chemical composition and anti-inflammatory activity of the essential oils of Piper gaudichaudianum and Piper mikanianum

Biological activity of essential oil from Piper mikanianum leaves and its major compound against storage pests and fungi

The use of synthetic insecticides and fungicides is the main method for controlling of coleopteran pests and fungal contamination during storage. However, intensive use of these products has caused several negative impacts. Thus, as an effective and safer alternative, essential oils (EOs) are a promising and efficient solution for integrated management in storage systems. The present study aimed to investigate the biological activity of Piper mikanianum EO against storage pests and fungi. The EO was extracted by hydro-distillation for 4 h, and the chemical composition was determined by gas chromatography coupled to mass spectrometry. A total of 29 compounds were identified in P. mikanianum EO, with safrole as the major compound, corresponding to 30.46%. This compound was later isolated by crystallization. The insecticidal effect of P. mikanianum EO and safrole was evaluated by fumigation, causing 100% mortality of Sitophilus zeamais, Sitophilus oryzae, Cryptolestes ferrugineus, and Rhyzopertha dominica at 138.38 μL L-1 of air. The fungicidal activity was assessed by volatilization and direct contact against Fusarium graminearum. Piper mikanianum EO and safrole inhibited fungal growth by volatilization at 92% and 78.3%, respectively, at a 100% concentration; by contact, both treatments caused inhibition above 90% at a 1.5% concentration. Safrole showed a lower value (0.5%) of minimum inhibitory concentration compared to EO (1.5%) by contact. These results confirmed the potential of P. mikanianum EO and its main compound, safrole, as biopesticides in the combined management of storage pests and diseases, proving to be a promising alternative to synthetic pesticides.

Circadian Analysis in Volatile Organic Compounds from Piper gaudichaudianum Kunth Fruits and Their Potential Role in Attracting Carollia perspicillata Bats

Piper fruits are one of the main dietary sources of Carollia perspicillata, a fruit-eating bat largely responsible for dispersing their seeds. To investigate the mechanism of this plant-animal interaction, ripe and unripe fruits of Piper gaudichaudianum were collected in the morning, afternoon, and night. The volatile organic compounds (VOC) were obtained through dynamic headspace (HS) and hydrodistillation (HD) and were analyzed by gas chromatography with flame ionization detector and GC-MS, resulting in the identification of ninety-five compounds. The principal component analysis of all samples revealed a distinction between the VOC obtained by the two techniques as well as differentiated the degree of ripeness of the fruits. The VOC compositions of fruits collected at night by HS and HD showed differences concerning those gathered in the morning and afternoon. The presence of linalool exclusively in the composition of ripe fruits collected at night and the highest levels of aromadendrene and (E)-nerolidol were also found in these samples, suggesting that these compounds may be responsible for attracting the bats and/or indicating the degree of fruit ripening. The chemical interaction between VOCs and bats appears to be more complex than simply considering the main compounds, encouraging additional tests to investigate the main compounds and their possible synergistic interactions.

Essential oil of Pterocarpus santalinus L. alleviates behavioral impairments in social defeat stress-exposed mice by regulating neurotransmission and neuroinflammation

BACKGROUND

Pterocarpus santalinus L. essential oil (PSEO) is traditionally employed for treating fever and mental aberrations. We aim to explore the antidepressant potential of intranasal PSEO in social defeat stress (SDS)-expose mice and identify its mechanisms and components.

METHODS

PSEO components were analyzed using gas chromatography-mass spectrometry (GC-MS). C57BL/6 mice underwent a 10-day SDS with intranasal PSEO (10, 20 mg/kg) for 21 days. Efficacy was evaluated through changes in behaviors and serum corticosterone (CORT), hippocampal neurotransmitter, and inflammatory cytokine levels. In vitro effects were examined using primary hippocampal neurons, PC12 and BV2 cells.

RESULTS

GC-MS identified 22 volatile compounds in PSEO, and (+)-ledene (16.7%), cedrol (13.5%), and isoaromadendrene epoxide (7.0%) as major components. PSEO (20 mg/kg) significantly reversed SDS-induced social withdrawal, increased open-area explorations in the open field test (OFT) and elevated plus maze (EPM) test, and reduced immobility time in the tail suspension test (TST) and forced swimming test (FST). PSEO downregulated serum CORT and hippocampal interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α levels, while increasing hippocampal gamma-aminobutyric acid (GABA), norepinephrine (NE), and serotonin (5-HT) levels. PSEO (0.1, 1, 10 µg/mL) reduced neurotoxicity and neuroinflammation in PC12 and BV2 cells, respectively. PSEO (10 µg/mL) enhanced glutamic acid decarboxylase 6 (GAD6)- and GABA B receptor 1 (GABABR1)-positive puncta in the hippocampal neurons and FM1-43 fluorescence intensity.

CONCLUSION

Intranasal PSEO exhibited antidepressant-like effects on SDS-exposed mice, potentially through modulating stress hormone, neurotransmission, and neuroinflammation. Further investigation into the pharmacokinetics, bioavailability, and mechanisms of (+)-ledene, cedrol, and isoaromadendrene epoxide is needed.

In-Silico Selection of Wound-Healing Plant Secondary Molecules and Their Pro-Healing Activities on Experimental Models

This study explored the potential of plant-derived molecules (PDMs) as a medicinal treatment for skin wounds. To assess their healing properties, 34 potential drug molecules (PDMs) and ten therapeutic targets were subjected to molecular docking and dynamics analysis, with allantoin used as a standard compound. Although aristolochic acid had the most potent inhibitory effect, its toxicity made it unsuitable for testing on cells and mice. Therefore, β-caryophyllene (BC) and caryophyllene oxide (BCoxide) were chosen for further testing. The results showed that BC-treated HaCat cells had significantly improved scratch area closure, and both BC and BCoxide treatment produced positive effects such as reduced dermal cellularity and mast cells, decreased levels of inflammation markers IL-6 and TNF-α, and an increase in collagen deposition in mice tissues. However, these treatments did not accelerate wound healing. This study suggests that the PDMs selected based on in-silico results have significant potential for pro-healing abilities. It is essential to conduct further research to confirm our findings.

Effect of ethanolic extracts from Piperaceae leaves on the reduction of skin necrosis and wound healing in an animal model of degloving injuries

PURPOSE

To assess the effect of the ethanolic extract of the leaves of three species of plants from the Piperaceae family on reducing necrosis and enhancing wound healing in an animal model of degloving injuries.

METHODS

The animals were divided into six groups, each consisting of six animals: sham, negative control, EEPA (Piper amalago ethanolic extract), EEPG (Piper glabratum ethanolic extract), EEPV (Piper vicosanum ethanolic extract), and positive control receiving hyperbaric oxygenation. The animals underwent surgery to induce excision wounds, and the extent of cutaneous necrosis was evaluated using graphic software, while wound healing was assessed through histopathology.

RESULTS

Skin necrosis percentage area was: sham group = 62.84% 6.38; negative control group = 63.03% 4.11; P. vicosanum = 40.80% 4.76 p < 0.05; P. glabratum 32.97% 4.01 p < 0.01; P. amalago = 32.40% 4.61 p < 0.01; hyperbaric oxygenation = 33.21% 4.29 p < 0.01. All treated groups showed higher collagen deposition and less intense, plus predominantly mononuclear inflammatory infiltrate, suggesting improved healing process.

CONCLUSIONS

The three tested extracts demonstrated efficacy in reducing the extent of cutaneous necrosis caused by degloving injuries and also showed evidence of improvement in the wound healing process.

Composition and Biological Activity of the Essential Oils from Wild Horsemint, Yarrow, and Yampah from Subalpine Meadows in Southwestern Montana: Immunomodulatory Activity of Dillapiole

Agastache urticifolia (Benth.) Kuntze (horsemint), Achillea millefolium L. (yarrow), and Perideridia gairdneri (Hook. & Arn.) Mathias (yampah) are native, culturally important plants that grow in the subalpine meadows of Montana. Analysis of the composition of essential oils extracted from these plants showed that the main components of essential oils obtained from flowers and leaves of A. urticifolia (designated as AUF/AUL) were menthone (2.7/25.7%), isomenthone (2.6/29.1%), pulegone (78.9/28.8%), and limonene (4.2/6.2%), whereas essential oils obtained from the inflorescence of A. millefolium (designated as AMI) were high in α-thujone (17.1%) and β-thujone (14.9%), 1,8-cineole (17.0%), camphor (13.0%), sabinene (7.0%), guaia-3,9-dien-11-ol (3.2%), and terpinen-4-ol (2.5%). Essential oils obtained from the inflorescence of P. gairdneri (designated as PGI) contained high amounts of dillapiole (30.3%), p-cymen-8-ol (14.1%), terpinolene (12.0%), 4-hydroxy-4-methyl-cyclohex-2-enone (6.2%), and γ-terpinene (2.4%). Evaluation of their immunomodulatory activity demonstrated that essential oils extracted from all of these plants could activate human neutrophils with varying efficacy. Analysis of individual components showed that dillapiole activated human neutrophil intracellular Ca²⁺ flux ([Ca²⁺]_i) (EC₅₀ = 19.3 ± 1.4 μM), while α-thujone, β-thujone, menthone, isomenthone, and pulegone were inactive. Since dillapiole activated neutrophils, we also evaluated if it was able to down-regulate neutrophil responses to subsequent agonist activation and found that pretreatment with dillapiole inhibited neutrophil activation by the chemoattractant fMLF (IC₅₀ = 34.3 ± 2.1 μM). Pretreatment with P. gairdneri essential oil or dillapiole also inhibited neutrophil chemotaxis induced by fMLF, suggesting these treatments could down-regulate human neutrophil responses to inflammatory chemoattractants. Thus, dillapiole may be a novel modulator of human neutrophil function.