Chemical composition, antimicrobial, and cytotoxicity studies on S. erianthum and S. macranthum essential oils

Therapeutic Effects of Essential Oils and Their Bioactive Compounds on Prostate Cancer Treatment

Since prostate cancer (PCa) relies on limited therapies, more effective alternatives are required. Essential oils (EOs) and their bioactive compounds are natural products that have many properties including anticancer activity. This review covers studies published between 2000 and 2023 and discusses the anti-prostate cancer mechanisms of the EOs from several plant species and their main bioactive compounds. It also provides a critical perspective regarding the challenges to be overcome until they reach the market. EOs from chamomile, cinnamon, Citrus species, turmeric, Cymbopogon species, ginger, lavender, Mentha species, rosemary, Salvia species, thyme and other species have been tested in different PCa cell lines and have shown excellent results, including the inhibition of cell growth and migration, the induction of apoptosis, modulation in the expression of apoptotic and anti-apoptotic genes and the suppression of angiogenesis. The most challenging aspects of EOs, which limit their clinical uses, are their highly lipophilic nature, physicochemical instability, photosensitivity, high volatility and composition variability. The processing of EO-based products in the pharmaceutical field may be an interesting alternative to circumvent EOs' limitations, resulting in several benefits in their further clinical use. Identifying their bioactive compounds, therapeutic effects and chemical structures could open new perspectives for innovative developments in the field. Moreover, this could be helpful in obtaining versatile chemical synthesis routes and/or biotechnological drug production strategies, providing an accurate, safe and sustainable source of these bioactive compounds, while looking at their use as gold-standard therapy in the close future.

Impacts of algae supplements (Arthrospira & Chlorella) on growth, nutrient variables, intestinal efficacy, and antioxidants in New Zealand white rabbits

An 8-week trial to examine the impacts of Arthrospira platensis and Chlorella vulgaris on the growth, nutrient aspects, intestinal efficacy, and antioxidants of 75 New Zealand white male rabbits (initial body weight = 665.93 ± 15.18 g). Herein the study was designed in one-way ANOVA to compare the effects of the two algae species with two levels of supplementations in the feeds of New Zealand white rabbits. The rabbits were divided into five groups (n = 15/group), where the first group was allocated as the control group (Ctrl) while the second and third groups received A. platensis at 300 or 500 mg/kg diet (Ap300 or Ap500). The fourth and fifth groups fed C. vulgaris at 300 or 500 mg/kg diet (Ch300 or Ch500). The basal diet rabbits exhibited the lowest values of weight, lipase, protease, and the highest feed conversion ratio, which improved noticeably with algae addition, particularly with Ap500, Ch300, and Ch500. All tested groups showed normal intestinal structure. Amylase potency, hematological indicators, and serum biochemistry revealed non-significant variation except for a higher serum total protein and lower total cholesterol in algal groups. The best GPx existed in groups fed algal diets, while favorable SOD and CAT efficiency occurred at the higher level of Arthrospira and both levels of Chlorella. In conclusion, incorporating Arthrospira or Chlorella in the diet of New Zealand white rabbits improved performance, nutrient utilization, intestinal efficacy, and antioxidants. Arthrospira (Ap500) and Chlorella (Ch300 or Ch500) have almost the same beneficial effect on rabbit performance.

Noninvasive Detection of Stress by Biochemical Profiles from the Skin

Stress is a leading cause of several disease types, yet it is underdiagnosed as current diagnostic methods are mainly based on self-reporting and interviews that are highly subjective, inaccurate, and unsuitable for monitoring. Although some physiological measurements exist (e.g., heart rate variability and cortisol), there are no reliable biological tests that quantify the amount of stress and monitor it in real time. In this article, we report a novel way to measure stress quickly, noninvasively, and accurately. The overall detection approach is based on measuring volatile organic compounds (VOCs) emitted from the skin in response to stress. Sprague Dawley male rats (n = 16) were exposed to underwater trauma. Sixteen naive rats served as a control group (n = 16). VOCs were measured before, during, and after induction of the traumatic event, by gas chromatography linked with mass spectrometry determination and quantification, and an artificially intelligent nanoarray for easy, inexpensive, and portable sensing of the VOCs. An elevated plus maze during and after the induction of stress was used to evaluate the stress response of the rats, and machine learning was used for the development and validation of a computational stress model at each time point. A logistic model classifier with stepwise selection yielded a 66-88% accuracy in detecting stress with a single VOC (2-hydroxy-2-methyl-propanoic acid), and an SVM (support vector machine) model showed a 66-72% accuracy in detecting stress with the artificially intelligent nanoarray. The current study highlights the potential of VOCs as a noninvasive, automatic, and real-time stress predictor for mental health.

Evaluation of the Active Ingredient of Campsis radicans Essential Oils and its Antimicrobial Evaluation Against Pathogenic Bacteria

Owing to the resistance of nosocomial pathogens to antibiotics, the need for herbal medicines is felt. The aim of this study was to identify the chemical composition of bark essential oils of Campsis radicans and the effect of its free and encapsulated form on resistant nosocomial pathogens. This plant is a native of Northern Iran. The Bark essential oils of Campsis radicans was first extracted and its antimicrobial effects were investigated. Then, its phytochemical compounds were determined using Gas Chromatography-Mass Spectrometry (GC/MS). Guaiacol (2-methoxy phenol) was selected as the active ingredient among 32 compounds (2.40%). It was encapsulated and the encapsulation efficiency (EE), the particle size, polydispersity index (pdi), Fourier transform infrared (FTIR), release, and stability were determined. Then, the antimicrobial effect of both free and encapsulated forms was evaluated on cotrimoxazole-resistant Pseudomonas aeruginosa, cefixime-resistant Escherichia coli, and fluconazole-resistant Candida albicans. It was observed that both free and encapsulated forms of Guaiacol had an antimicrobial effect on the studied resistant strains, but the encapsulated form had a more antimicrobial effect due to more stability and a more targeted effect. MBC (MFC) ranged from 0.270 to 0.439 µg/ml in the free form and from 0.055 to 0.133 µg/ml in the encapsulated form, EE was 86%, particle size, and pdi were 138 nm and 0.26, respectively. This study showed that this plant can be a suitable alternative to chemical drugs due to its antimicrobial effects.

A Narrative Review on the Bioactivity and Health Benefits of Alpha-Phellandrene

Aromatic essential oils play a significant role in pharmaceuticals, food additives, cosmetics, and perfumery. Essential oils mostly comprise aliphatic hydrocarbons, monoterpenoids, sesquiterpenoids and diterpenes. Plant extracts comprise a complex mixture of terpenes, terpenoids, aliphatic and phenol-derived aromatic components. Terpenes are a significant class of hydrocarbons with numerous health benefits. These biological functions of essential oil components are examined in vitro and in vivo studies. Some studies evaluated the properties and functions of α-phellandrene (α-PHE). Detailed evaluation to determine the functions of α-PHE over a spectrum of health care domains needs to be initiated. Its possible mechanism of action in a biological system could reveal the future opportunities and challenges in using α-PHE as a pharmaceutical candidate. The biological functions of α-PHE are reported, including anti-microbial, insecticidal, anti-inflammatory, anti-cancer, wound healing, analgesic, and neuronal responses. The present narrative review summarizes the synthesis, biotransformation, atmospheric emission, properties, and biological activities of α-PHE. The literature review suggests that extended pre-clinical studies are necessary to develop α-PHE-based adjuvant therapeutic approaches.

Whole-cell bacterial biosensor for volatile detection from Pectobacterium-infected potatoes enables early identification of potato tuber soft rot disease

Half of the harvested food is lost due to rots caused by microorganisms. Plants emit various volatile organic compounds (VOCs) into their surrounding environment, and the VOC profiles of healthy crops are altered upon infection. In this study, a whole-cell bacterial biosensor was used for the early identification of potato tuber soft rot disease caused by the pectinolytic bacteria Pectobacterium in potato tubers. The detection is based on monitoring the luminescent responses of the bacteria panel to changes in the VOC profile following inoculation. First, gas chromatography-mass spectrometry (GC-MS) was used to specify the differences between the VOC patterns of the inoculated and non-inoculated potato tubers during early infection. Five VOCs were identified, 1-octanol, phenylethyl alcohol, 2-ethyl hexanol, nonanal, and 1-octen-3-ol. Then, the infection was detected by the bioreporter bacterial panel, firstly measured in a 96-well plate in solution, and then also tested in potato plugs and validated in whole tubers. Examination of the bacterial panel responses showed an extensive cytotoxic effect over the testing period, as seen by the elevated induction factor (IF) values in the bacterial strain TV1061 after exposure to both potato plugs and whole tubers. Moreover, quorum sensing influences were also observed by the elevated IF values in the bacterial strain K802NR. The developed whole-cell biosensor system based on bacterial detection will allow more efficient crop management during postharvest, storage, and transport of crops, to reduce food losses.

Solanum pubescens wild fruits essential oil - A golden casket for its antimicrobial and anti-inflammatory mediated wound healing efficacy in vertebrate model Mus musculus

BACKGROUND

Solanum pubescens Willd, growing wild in the hills of Rayadurg jurisdiction of Southwestern Andhra Pradesh, has gained significant attention among researchers for its diverse folkloric applications, existence of novel phytochemicals and leaf extracts which hold great medicinal promises. To date, the S. pubescens fruit's essential oil (SPO) has never been investigated.

METHODS

The current research has been focused to evaluate the chemical composition of S. pubescens fruit essential oil through Gas Chromatography-Mass Spectrometry (GC-MS), followed by the investigation of antibacterial, antifungal, anti-inflammatory, analgesic and wound healing activities in appropriate models to uncover its biological potentials. Extraction of (Solanopuboil/SPO) from the fresh unripe fruits of Solanum pubescens was carried out in Buchner funnel and Whatman no.10 filter paper and concentrated at 40oC using a rotary evaporator. The metabolic profiling of SPO was analysed by GC-MS technique. The MIC, MBC, activity index, and total antimicrobial activity of SPO were evaluated using standard procedures. Anti-inflammatory activity of SPO was screened using Carrageenan induced paw oedema and Cotton pellet-induced granuloma. Tail immersion test, Acetic acid writhing response and Formalin paw lick test was performed in rats in order to examine the analgesic activity of SPO. Wound healing activity of SPO was investigated by performing the incision wound model, Excision wound model and Dead space wound model in rats.

RESULTS

The SPO displayed a constant degree of antimicrobial activity against B. cereus, B. subtilis, E. coli, A. niger, A. fumigatus and C. albicans with significant anti-inflammatory and analgesic activities. Also, a prominent wound healing potential of it was observed in excision, incision and dead space wound models with considerable elevation in granulation tissue hydroxyproline, hexuronic acid and hexosamine content in association with remarkable regulation of anti-inflammatory and antioxidant markers i.e., Lipid peroxidase (LPO), Nitric Oxide (NO), Superoxide dismutase (SOD), Glutathione (GSH), Catalase (CAT), Glutathione Peroxidase (GPx).

CONCLUSION

These findings strongly validate the therapeutic potential of S. pubescens fruit essential oil in antimicrobial and anti-inflammatory mediated wound healing and suggests its promising application as valuable and novel indigenous leads in the food and pharmaceutical industries. To the best of our knowledge, this is the first-ever investigatory report on the systematic phytochemical and therapeutic examination of S. pubescens fruit essential oil.

Chemical Composition Analysis, Antioxidant, and Antibacterial Activities of Eggplant Leaves

Agricultural by-products represent one of the biggest pollutants for the environment, therefore, investigating new sources for the extraction of bioactive compounds is a topic of great interest for the entire scientific community. This work is aimed at studying the chemical composition (pigments, phenolics, volatile compounds) and biological activities (antioxidant and antimicrobial properties) of young and mature leaves of five eggplant cultivars (Solanum melongena L.) grown in Tunisia (Tizona, A1014, Nawel, A336, and Mirval). Pigment analysis showed no statistical variations between the two types of leaves, whereas higher levels of anthocyanins were recorded in young leaves of three out of five cultivars (24.7-52.8 mg 100 g^-1 ). Total phenolic compounds (966.5-2072.6 mg 100 g^-1 ) and o-diphenols (343.9-741.2 mg 100 g^-1 ) contents varied significantly according to leaf age and cultivar. However, no statistically significant variation between young and mature leaves was found in flavonols and tannins content. As for volatile profiles, 62 constituents were characterized with non-terpene derivatives (52.0-61.6 %) and apocarotenes (19.9-35.6 %) as major chemical classes. Regarding the antioxidant activity, methanol extracts of Tizona cultivar mature leaves displayed important antiradical properties using DPPH, ABTS, and phosphomolybdenum assays (IC₅₀ 0.1, 0.2 and 0.01 mg mL^-1 , respectively). With regards to reducing power determination, the most active extract was obtained from mature A1014 leaves. Further, young Mirval leaves proved to be significantly active from a bactericidal point of view against Candida albicans and Staphylococcus aureus of 3.1 mg mL^-1 and 0.2 mg mL^-1 MBC, respectively. In conclusion, eggplant leaves are a noteworthy source of antioxidant and antimicrobial compounds with potential use in the pharmaceutical, the cosmetics and the food industries.

Chemical characterisation of essential oils of leaves of two Solanaceae: Solanum rugosum and Solanum erianthum from Côte d'Ivoire

This study made it possible to characterise by GC (in combination with retention indices), GC-MS and ¹³C NMR, the chemical composition of the essential oils from Solanum rugosum and Solanum erianthum, two Solanaceae of the Ivorian flora. The two essential oils were characterised by a very high proportion of sesquiterpenes. Specifically, the essential oil of S. rugosum was dominated by (E)-β-caryophyllene (33.7%), β-elemol (19.8%) and germacrene D (14.4%), while that of S. erianthum was mainly composed of α-humulene (38.6%), β-elemol (17.8%) and (E)-β-caryophyllene (16.7%). The chemical composition of Solanum rugosum is described here for the first time.

Lipophilic Metabolites and Anatomical Acclimatization of Cleome amblyocarpa in the Drought and Extra-Water Areas of the Arid Desert of UAE

Plants adapt to different environmental conditions by developing structural and metabolic mechanisms. In this study, anatomical features and lipophilic metabolites were investigated in Cleome amblyocarpa Barr. & Murb., Cleomaceae plants growing in the arid desert of United Arab Emirates (UAE) in either low-water or extra-water areas, which were caused by the surrounding road run-off. The plant showed the presence of shaggy-like trichomes. The plant also developed special mechanisms to ensure its survival via release of lipophilic metabolites. The lipophilic metabolites, stained red with Sudan III, were apparently released by glandular trichomes and idioblasts of the shoot and roots, respectively. The identified lipophilic metabolites included those required for drought tolerance, protection against pathogens invasion, and detoxification. Plants growing in the low-water area caused an increase in the production of lipophilic metabolites-in particular, hydrocarbons and terpenoids. The lipophilic metabolites are known to provide the plant with unique waxy surfaces that reduce water loss and avoid penetration by pathogens. The release of lipid metabolites and the presence of shaggy-like trichomes represented unique features of the species that have never been reported. The provided chemical ecology information can be extended for several plant-related applications, particularly including drought tolerance.

α-Phellandrene enhances the immune response and resistance against Vibrio alginolyticus in white shrimp (Litopenaeus vannamei)

Innate immunity and resistance against Vibrio alginolyticus in white shrimp, Litopenaeus vannamei, that received α-phellandrene were examined. The results indicated that the percent survival of shrimp receiving 4, 8, and 12 μg g^-1 α-phellandrene was significantly higher than that of control shrimp after 72 h (p < 0.05). In a separate experiment, the phenoloxidase (PO), respiratory bursts, superoxide dismutase (SOD), and phagocytic and lysozyme activity of L. vannamei receiving 8 and 12 μg g^-1 α-phellandrene were significantly higher than those of the other groups upon challenge with V. alginolyticus at 24-60, 36-60, 12-60, 12-72 and 48-72 h, respectively. However, no significant differences in the total haemocyte counts (THC) of L. vannamei receiving any dose of α-phellandrene and of control shrimp were observed at 12-72 h. The expression (mRNA transcripts) of the immune genes prophenoloxidase (proPO), LPS- and β-1,3-glucan-binding protein (LGBP) and peroxinectin (PE) of shrimp receiving α-phellandrene at 8 and 12 μg g^-1 significantly increased after challenge with V. alginolyticus for 72 h (p < 0.05). We conclude that the immune ability and resistance against V. alginolyticus infection increased in L. vannamei receiving >4 μg g^-1 α-phellandrene. These results indicated that α-phellandrene plays an important role in the innate immunity of white shrimp.

Cymbopogon citratus and Cymbopogon giganteus essential oils have cytotoxic effects on tumor cell cultures. Identification of citral as a new putative anti-proliferative molecule

Cymbopogon species are used as traditional remedies in Burkina Faso for treating several diseases. We aimed to study the effects of their essential oils on cancer cell lines. For that purpose, Cymbopogon citratus (DC.) Stapf. and Cymbopogon giganteus Chiov. were studied for their essential oils after various chemical extractions. Antioxidant, potential anti-inflammatory action (inhibition of lipoxygenase) and cytotoxic activities were also tested on various prostate cancer and glioblastoma cell lines. Thirty-three compounds were identified in the essential oil of C. giganteus: Limonene (19.33%), Mentha-1(7),8-dien-2-ol cis (17.34%), Mentha-1(7),8-dien-2-ol trans (13.95%), trans-Mentha-2,8-diene-para-ol 1 (13.91%) and Mentha-2,8-diene-1-ol, cis-para (8.10%) were the most abundant. C. citratus essential oil contained 15 compounds and the major ones were geranial/citral A (48.18%) and neral/citral B (34.37%). Essential oil of C. citratus showed the highest ability to scavenge DPPH⁺ radicals (approximately 68% at 8 mg/mL) while C. giganteus exhibited the highest capability to reduce ABTS⁺ (0.59μmolET/g). The essential oil of C. citratus was the most effective on prostate cell lines LNCaP (IC₅₀ = 6.36 μg/ml) and PC-3 (IC₅₀ = 32.1 μg/ml), and on glioblastoma cell lines (SF-767 (IC₅₀ = 45.13 μg/ml) and SF-763 (IC₅₀ = 172.05 μg/ml). Interestingly, the activity of essential oil of C. citratus was statistically equal to that of its major component, citral. Combination of both oils showed antagonist, additive, indifferent and synergistic effects on LNCaP, PC-3, SF-767 and SF-763 cell lines, respectively. In conclusion, plants from the traditional medicine in Burkina Faso could be of interest for identifying new compounds, such as citral, for the treatment of prostate cancer and glioblastoma.

Analgesic-Like Activity of Essential Oil Constituents: An Update

The constituents of essential oils are widely found in foods and aromatic plants giving characteristic odor and flavor. However, pharmacological studies evidence its therapeutic potential for the treatment of several diseases and promising use as compounds with analgesic-like action. Considering that pain affects a significant part of the world population and the need for the development of new analgesics, this review reports on the current studies of essential oils’ chemical constituents with analgesic-like activity, including a description of their mechanisms of action and chemical aspects.

Biological Activities of Essential Oils: From Plant Chemoecology to Traditional Healing Systems

Essential oils are complex mixtures of hydrocarbons and their oxygenated derivatives arising from two different isoprenoid pathways. Essential oils are produced by glandular trichomes and other secretory structures, specialized secretory tissues mainly diffused onto the surface of plant organs, particularly flowers and leaves, thus exerting a pivotal ecological role in plant. In addition, essential oils have been used, since ancient times, in many different traditional healing systems all over the world, because of their biological activities. Many preclinical studies have documented antimicrobial, antioxidant, anti-inflammatory and anticancer activities of essential oils in a number of cell and animal models, also elucidating their mechanism of action and pharmacological targets, though the paucity of in human studies limits the potential of essential oils as effective and safe phytotherapeutic agents. More well-designed clinical trials are needed in order to ascertain the real efficacy and safety of these plant products.

Induction of α-Phellandrene on Autophagy in Human Liver Tumor Cells

α-Phellandrene (α-PA) is a cyclic monoterpene. To investigate the induction of autophagy by α-PA and its mechanism, human liver tumor cells (J5) were incubated with α-PA and analyzed for cell viability and the molecular regulation of pre-autophagosome origination and autophagosome formation. According to the results, PI3K-I, mTOR, and Akt protein levels were decreased after α-PA treatment compared to those of the control group (p < 0.05). The phosphorylation of Bcl-2, and PI3K-III, LC3-II and Beclin-1 protein levels in J5 cells were increased after α-PA treatment (p < 0.05). In addition, α-PA up-regulated nuclear p53 and down-regulated cytoplasmic p53 expression in J5 cells. The NF-κB pathway was activated, as indicated by increase in cytosolic phosphorylated IκB, nuclear NF-κB levels, and the DNA-binding activity of NF-κB after α-PA treatment in J5 cells (p < 0.05). These results suggest that α-PA can induce J5 cell autophagy by regulating mTOR and LC-3II expression, p53 signaling, and NF-κB activation in J5 cells.

Volatile Constituents from the Leaves, Fruits (Berries), Stems and Roots of Solanum xanthocarpum from Nepal

The essential oils from the leaves, fruits, roots, and stems of Solanum xanthocarpum, growing wild in Nepal, have been obtained and analyzed by gas chromatography – mass spectrometry. The fruit volatiles were dominated by benzyl benzoate (21.7%) and ( E, E)-geranyl linalool (12.6%); heptacosane (20.0%) was the major component of the leaf oil; the stem oil was dominated by palmitic acid (28.9%), heptacosane (12.8%) and linoleic acid (10.1%); while solavetivone (22.9%), palmitic acid (21.0%), and linoleic acid (8.2%) were the major components of the root essential oil. There do not seem to be any common phytochemical taxonomic markers in the essential oils of Solanum spp; the chemical diversity observed in this genus mirrors the taxonomic diversity.

Induction of necrosis in human liver tumor cells by α-phellandrene

α-Phellandrene (α-PA) is a component of dietary spices and herbs. The effect of α-PA on anticancer is unclear. This study aims to investigate the effects of α-PA on liver tumor cell death fate. Human liver tumor (J5) cells were incubated with α-PA and analyzed for cell cycle distribution, expression of Bax, Bcl-2, poly (ADP-ribose) polymerase (PARP) protein, and caspase-3 activity of J5 cells, and levels of nitric oxide (NO) production, lactate dehydrogenase (LDH) leakage, and ATP depletion were also analyzed in this study. Results found that α-PA significantly (P < 0.05) decreased the cell viability of J5 cells after 24-h treatment. The cell cycle distribution, Bax, Bcl-2, PARP protein levels, and caspase-3 activity of J5 cells did not change for 24 h after treatment with 30 μM α-PA. Reactive oxygen species levels significantly increased, mitochondrial membrane potential levels significantly decreased when J5 cells were treated with 30 μM α-PA for 24 h (P < 0.05). Thirty μM α-PA significantly (P < 0.05) increased the necrotic cell number, NO production, LDH leakage, and ATP depletion after 24 h of incubation. These results suggest that α-PA induced J5 cell necrosis but not apoptosis, and α-PA-induced necrosis possibly involved ATP depletion.

Regeneration of Solanum nigrum by somatic embryogenesis, involving frog egg-like body, a novel structure

A new protocol was established for the regeneration of Solanum nigrum by frog egg-like bodies (FELBs), which are novel somatic embryogenesis (SE) structures induced from the root, stem, and leaf explants. The root, stem, and leaf explants (93.33%, 85.10%, and 100.00%, respectively) were induced to form special embryonic calli on Murashige and Skoog (MS) medium containing 1.0 mg/L 2,4-dichlorophenoxyacetic acid, under dark condition. Further, special embryonic calli from the root, stem, and leaf explants (86.97%, 83.30%, and 99.47%, respectively) were developed into FELBs. Plantlets of FELBs from the three explants were induced in vitro on MS medium supplemented with 5.0 mg/L 6-benzylaminopurine and 0.1 mg/L gibberellic acid, and 100.00% plantlet induction rates were noted. However, plantlet induction in vivo on MS medium supplemented with 20 mg/L thidiazuron showed rates of 38.63%, 15.63%, and 61.30% for the root, stem, and leaf explants, respectively, which were lower than those of the in vitro culture. Morphological and histological analyses of FELBs at different development stages revealed that they are a novel type of SE structure that developed from the mesophyll (leaf) or cortex (stem and root) cells of S. nigrum.

Cytotoxic Activity of Essential Oils of Aerial Parts and Ripe Fruits of Echinophora spinosa (Apiaceae)

The cytotoxic effects of the essential oils obtained from the flowering aerial parts (APO) and ripe fruits (RFO) of Echinophora spinosa L. (Apiaceae) from central Italy toward human U937 promonocytoid cells were studied; the contribution of each of the major constituents to the whole cytotoxic activity of either APO or RFO was also characterized. The major components of APO were β-phellandrene (34.7%), myristicin (16.5%), p-cymene (16.3%), δ3-carene (12.6%), α-pinene (6.7%) and α-phellandrene (6.2%); those of RFO p-cymene (50.2%), myristicin (15.3%), α-pinene (15.1%) and α-phellandrene (8.1%). Both oils tested were toxic to U937 cells, but RFO was much more cytotoxic: indeed, the IC50 values calculated from the linear regression curves of RFO and APO were 14.5 ± 0.85 and 43.4 ± 2.81 μg/mL, respectively. α-Pinene and α-phellandrene were identified as the most toxically relevant constituents: however, they did not completely account for the toxic effects of genuine APO and RFO. Interestingly, we found that p-cymene, although per se devoid of toxicity within the tested range of concentrations, was capable of significantly sensitizing U937 cells to the cytotoxic activity of α-pinene and α-phellandrene, and that specific mixtures of these three terpenes were as toxic as genuine APO and RFO.

The essential oils chemical compositions and antimicrobial, antioxidant activities and toxicity of three Hyptis species

CONTEXT

Hyptis suaveolens (Linn.) Poit., Hyptis rhomboidea Mart. et Gal., and Hyptis brevipes Poit., are three species of Hyptis Jacq. (Lamiaceae). Hyptis suaveolens is used for the treatment of fever, headache, gastrointestinal bloating and rheumatism in the traditional folk medicine; Hyptis rhomboidea for hepatitis, ulcer and swollen poison; and Hyptis brevipes for asthma and malaria.

OBJECTIVE

To characterize chemical compositions of the oils from three Hyptis species and evaluate their potential antimicrobial, radical scavenging activities and toxicities against brine shrimp.

MATERIALS AND METHODS

The oils were obtained by hydrodistillation, and their chemical compositions were investigated by gas chromatography-mass spectrometry (GC-MS). Minimum inhibitory concentrations (MICs) were determined using the tube double-dilution technique. The antioxidant activities were investigated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and toxicities by the brine shrimp bioassay.

RESULTS

Forty-seven, 33 and 28 constituents of oils isolated, respectively, from H. suaveolens, H. rhomboidea and H. brevipes were identified. Among the essential oils, the strongest antioxidant activity was exhibited by H. brevipes with an SC₅₀ value of 2.019 ± 0.25 μg mL⁻¹. The H. brevipes oil exhibited the strongest antimicrobial activity (3.125-6.25 μg mL⁻¹) on pathogens employed in the assay. They all showed significant toxicities with median lethal concentration (LC₅₀) values of 62.2 ± 3.07 μg mL⁻¹, 65.9 ± 6.55 μg mL⁻¹ and 60.8 ± 9.04 μg mL⁻¹, respectively.

DISCUSSION AND CONCLUSIONS

The three Hyptis species oils possess strong antimicrobial activities and toxicities. Hyptis rhomboidea and H. brevipes showed considerable antioxidant activity compared to the positive control.

Anti-inflammatory components from the root of Solanum erianthum

Two new norsesquiterpenoids, solanerianones A and B (1-2), together with nine known compounds, including four sesquiterpenoids, (-)-solavetivone (3), (+)-anhydro-β-rotunol (4), solafuranone (5), lycifuranone A (6); one alkaloid, N-trans-feruloyltyramine (7); one fatty acid, palmitic acid (8); one phenylalkanoid, acetovanillone (9), and two steroids, β-sitosterol (10) and stigmasterol (11) were isolated from the n-hexane-soluble part of the roots of Solanum erianthum. Their structures were elucidated on the basis of physical and spectroscopic data analyses. The anti-inflammatory activity of these isolates was monitored by nitric oxide (NO) production in lipopolysaccharide (LPS)-activated murine macrophage RAW264.7 cells. The cytotoxicity towards human lung squamous carcinoma (CH27), human hepatocellular carcinoma (Hep 3B), human oral squamous carcinoma (HSC-3) and human melanoma (M21) cell lines was also screened by using an MTT assay. Of the compounds tested, 3 exhibited the strongest NO inhibition with the average maximum inhibition (Emax) at 100 μM and median inhibitory concentration (IC50) values of 98.23% ± 0.08% and 65.54 ± 0.18 μM, respectively. None of compounds (1-9) was found to possess cytotoxic activity against human cancer cell lines at concentrations up to 30 μM.

Essential Oils from the Leaves of Six Medicinal Plants of Nigeria

The chemistry of Cassia siamea L., C. occidentalis L. (Fabaceae), Cnestis ferruginea Vahl ex DC (Connaraceae), Anthocleista djalonensis A. Chev (Loganiaceae), Solanum torvum Swartz and S. erianthum G. Don (Solanaceae) volatiles grown in Nigeria have been studied. The essential oils were obtained by hydrodistillation and analyzed by GC and GC-MS. The main compounds of C. siamea were (E)-geranyl acetone (5.8%), 1-octen-3-ol (5.8%), linalool (7.8%), iso-italicene (15.4%) and (E)-β-damascenone (11.0%). On the other hand, C. occidentalis consisted mainly of (E)-geranyl acetone (8.0%), hexahydrofarnesylacetone (24.0%) and (E)-phytol acetate (40.7%). The oil of C. ferruginea was comprised mainly of (E)-geranyl acetone (13.7%), (E)-α-ionone (9.5%), phytol (5.8%), pentadecanal (6.1%) and 1-octen-3-ol (5.5%). The main compounds of A. djalonensis were α-humulene (31.9%), β-caryophyllene (17.8%), humulene epoxide II (12.7%) and caryophyllene oxide (5.9%). The main volatiles of S. torvum were (E)-phytol acetate (38.7%), pentadecanal (25.3%) and (E)-geranyl acetone (5.0%). Apart from methyl salicylate (4.5%), tetradecanal (2.2%), 2-pentyl furan (1.8%), hexahydrofarnesylacetone (1.6%) and hexadecanal (1.1%), all other compounds were either present in trace quantity or in amounts less than 1%. On the other hand, α-humulene (46.6%) and β-caryophyllene (20.6%) were the compounds occurring in higher quantities in S. erianthum. The volatile oil contents of Cassia siamea, Cnestis ferruginea, Anthocleista djalonensis and Solanum torvum are being reported for the first time.

Chemical composition and biological activities of the essential oils from Duguetia lanceolata St. Hil. barks

Essential oils of Duguetia lanceolata barks, obtained at 2 (T2) and 4 h (T4), were identified by gas chromatography and gas chromatography/mass spectrometry. β-elemene (12.7 and 14.9%), caryophyllene oxide (12.4 and 10.7%) and β-selinene (8.4 and 10.4%) were the most abundant components in T2 and T4, respectively. The essential oils inhibited the growth of Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli and Candida albicans. The essential oils were cytotoxic against brine shrimp. The extraction time influenced the chemical composition and biological activities of essential oils obtained from the barks of D. lanceolata.