Chemical composition, antioxidative and antimicrobial activities of essential oil of wild Artemisia annua from Ningxia, China.

Artemisia annua is an essential aromatic medicinal plant endemic to China. Here, essential oil was extracted from wild A. annua from Ningxia, China. GC-MS analysis showed that A. annua essential oil was dominated by artemisia ketone, a characteristic compound accounting for 31.26%, followed by eucalyptol (14.89%), camphor (8.69%), myrcene (8.25%) and α-pinene (6.65%). The overall antioxidative potential represented by DPPH and ATBS free radical scavenging rates was weak. The essential oil exhibited good bactericidal activities against Escherichia coli and Staphylococcus aureus and fungicidal activities against Trichophyton rubrum and Epidermophyton floccosum. The minimum inhibitory and microbicidal concentrations were 0.02 mg/mL and 5.12 mg/mL for both bacteria, 0.315% and 2.5% for E. floccosum, and 0.625% and 5% for T. rubrum. The results suggest that A. annua essential oil may be an antimicrobial adjuvant to be applied in pharmaceutical and cosmetic industries.

Lavender essential oil fractions alleviate sleep disorders induced by the combination of anxiety and caffeine in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Lavender (Lavandula angustifolia Mill.) essential oil is renowned for its use in the treatment of insomnia and mental disorder diseases in folk medicine. Previous pharmacological studies have also shown that lavender essential oil displays sedative and hypnotic activities. However, the active ingredients and mechanism of lavender essential oil for sleep-improving effect remain unclear. AIM OF THE STUDY: This study investigates whether inhalation of different fractions of lavender essential oil can attenuate the sleep disturbances induced by combined anxiety and caffeine and explores the underlying mechanisms. MATERIALS AND METHODS: Molecular distillation was applied to separate lavender essential oil into fractions containing different chemical components, and GC-MS was used to analyze the volatile compounds of lavender essential oil and its fractions. The elevated plus maze test, pentobarbital-induced sleep test, and neurotransmitters enzyme-linked immunosorbent assay were conducted to evaluate the anxiolytic and hypnotic effects of lavender essential oil and its fractions on mice suffering from sleep disorders. RESULTS: The results of behavioral tests indicated that lavender essential oil and its fractions (3%, v/v) exerted an ameliorating effect on sleep disturbances induced by anxiety and caffeine. The light fraction and heavy fractions exhibited complementary chemical composition, with the former enriched in linalool and trans-ß-ocimene and the latter in linalyl acetate, lavandulyl acetate, trans-caryophyllene, etc. The light fraction contributed more to sleep maintenance, and the heavy fraction performed better at sleep initiation. The neurobiological parameters elucidated that the mechanism of lavender essential oil for sleep-improving was multifaceted, related to the GABAergic system, cholinergic system, histaminergic system, and monoamines in the limbic system. The heavy fraction shared a similar mechanism with the lavender essential oil, while the light fraction did not actively participate in the cholinergic system, histaminergic system, and dopaminergic system. CONCLUSION: Taken together, our results demonstrated that different fractions of lavender essential oil played different roles in ameliorating sleep disorders, and this may be credited to their compositional differences and the complicated interactions with the central nervous system. The results are informative for future investigations on the molecular level mechanisms and provide guidance for appropriate applications of lavender essential oil.

Antinociceptive effects of flower extracts and the active fraction from Styrax japonicus.

ETHNOPHARMACOLOGICAL RELEVANCE: Flowers from Styrax japonicus sieb. et Zucc. have been used as a Chinese folk medicine to alleviate pain such as toothache and sore throat. AIM OF THE STUDY: To testify the analgesic effect of flowers from Styrax japonicus, analyze components of the active fraction, and investigate the mechanism of analgesia. MATERIALS AND METHODS: Flower extracts were obtained by ethanol, petroleum ether and hydrodistillation extraction. Different fractions of ethanol extracts (EE) were isolated by silica gel column chromatography and preparative liquid chromatography. Analgesic effects of EE, petroleum ether extracts (PEE), hydrodistillation extracts (HDE), and fractions of EE were evaluated using hot plate, acetic acid-induced writhing and formalin tests on mice. Components of the active fraction 1 (F1) were determined by the ultrahigh-performance liquid chromatography Q extractive mass spectrometry (UHPLC-QE-MS). Anti-inflammatory and sedative effects involving analgesic mechanisms were evaluated by carrageenan induced hind paw oedema and pentobarbital sodium sleep tests, respectively. In addition, antagonists including naloxone hydrochloride (NXH), flumazenil (FM), SCH23390 (SCH) and WAY100635 (WAY) were used to investigate the possible mechanism of analgesia. Contents of neurotransmitters and relevant metabolites in different brain regions of mice were also quantified by the ultraperformance liquid chromatography with a fluorescence detector (UPLC-FLD). RESULTS: EE rather than PEE and HDE at medium and high doses (150 mg/kg and 300 mg/kg) significantly prolonged the latency time of the response of mice to the thermal stimulation in the hot plate test. Moreover, EE significantly decreased number of writhes in the acetic acid-induced writhing test, and reduced licking time in both two phases of the formalin test in a dose-dependent manner. The F1 (50 mg/kg) showed effective antinociceptive responses in all mice models. However, fraction 2 (F2) and fraction 3 (F3) at 50 mg/kg performed no analgesic action. Kaempferol-3-O-rutinoside, isorhamnetin-3-O-rutinoside, pinoresinol-4-O-glucoside, forsythin and arctiin were identified from components of the F1. Furthermore, F1 (50 mg/kg) did not significantly affect hind paw oedema of mice induced by carrageenan but significantly shortened sleep latency and increased sleep duration in the pentobarbital sodium sleep test. In addition, the antinociceptive response of F1 was not affected by NXH in two mice models, but significantly blocked by FM and WAY in the hot plate test. In the formalin test, FM avoided the effect of F1 only in the first phase, while the analgesic activity of F1 was totally suppressed by WAY in both two phases. Otherwise, contents of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) increased significantly in hippocampus and striatum of mice in the F1 group. CONCLUSION: EE from flowers of Styrax japonicus, and F1, the active part isolated from EE, showed significant antinociceptive activities. The analgesic effect of F1 appeared to be related to the sedative effect, partially mediated by the GABAergic system, and highly involved in the serotonergic system. This was the first study confirming the analgesic effect of Styrax japonicus flower, which provided a candidate for the development of non-opioid analgesics.

Anxiolytic Effect of Two Tobacco Essential Oils (Nicotiana tabacum Linn.) on Mice.

Tobacco (Nicotiana tabacum Linn.) is a famous traditional herb used in folk medicine. The essential oils of tobacco have been demonstrated in modern studies to possess antioxidant, anti-inflammatory, and neuroprotective properties, while its anxiolytic effect has not been reported. The purpose of this study was to evaluate the anxiolytic effect of Yunnan tobacco essential oil (YTO) and Zimbabwe tobacco essential oil (ZTO) on mice. The constituents of YTO and ZTO were analyzed by GC/MS. The anxiolytic effect of YTO and ZTO (0.1%, 1%, and 10%, v/v) on male ICR mice was evaluated in the light-dark box test (LDB) and the elevated plus maze test (EPM) test via inhalation and transdermal administration. After the behavioral tests, salivary corticosterone levels in mice were measured. The behavioral analysis showed that the administration of both YTO and ZTO elevated the time that the mice spent in the light chamber in the LDB test compared to the untreated control. In the EPM test, YTO and ZTO increased the time spent in open arms and the number of entries into the open arms. In addition, both YTO and ZTO significantly decreased salivary corticosterone levels in mice (p ≤ 0.001). In summary, our results demonstrated that inhalation and transdermal administration of both YTO and ZTO showed anxiolytic effect on male ICR mice.