Insecticidal and biochemical activity of essential oil from Citrus sinensis peel and constituents on Callosobrunchus maculatus and Sitophilus zeamais.

Essential oils are promising substitute for chemical pesticides with the inherent resistance by pests, environmental and health effects on humans. In this study, the chemical composition of essential oil extracted from Citrus sinensis peel was characterized, the insecticidal activities of the oil and its constituents against Callosobrunchus maculatus (Cowpea weevil) and Sitophilus zeamais (maize weevil) were investigated and the underlying insecticidal mechanism were elucidated. The essential oil was extracted by hydro-distillation and characterized using gas chromatography-mass spectrometry (GC-MS). Insecticidal activity was determined by contact and fumigant toxicity assay. The inhibitory effect of the oil and its constituents on acetylcholinesterase (AChE), Na+/K+-ATPase and glutathione-S- transferase (GST) activity were assayed using standard protocols. The total number of volatile compounds detected in C. sinensis essential oil was eighteen (18). d-limonene (59.3%), terpineol (8.31%) and linalool (6.88%) were the major compounds present in the essential oil. Among the tested essential oil compounds, terpineol showed highest contact toxicity against C. maculatus (LD50 =17.05 µg/adult) while 3-carene showed highest contact toxicity against S. zeamais (LD50 =26.01 µg/adult) at 24 h exposure time. Citral exhibited the highest fumigant toxicity against C. maculatus and S. zeamais with LC50 value 0.19 and 2.02 µL/L air at 24 h respectively. Acetylcholinesterase and Na+/K+-ATPase activities were significantly inhibited by C. sinensis oil and its constituents in both C. maculatus and S. zeamais as compared to control. This study indicates that C. sinensis essential oil and its constituents have potential to be developed into botanical pesticides.

Volatile constituents and biological activities of the leaf and root of Echinacea species from South Africa.

Echinacea is used ethnomedicinally for the treatment of various diseases such as cough, respiratory infections, and bronchitis among other uses in Eastern Cape region of South Africa. This study evaluated the volatile components of the essential oil of the plant, its toxicity, anti-inflammatory and analgesic activities in rodents. Dried leaf and root of the plant were separately processed by hydrodistillation for 4 h and their essential oils (EOs) were collected. Extracted oils were subjected to GC/GC-MS analysis. The essential oil was further evaluated for acute toxicity, anti-inflammatory and analgesic activities. The toxicity profile of the essential oil was evaluated in mice through the oral route (p.o.), and anti-inflammatory activity was evaluated on the carrageenan-induced edema model in rats at the doses of 100-200 mg/kg, while its analgesic effect was evaluated on the acetic acid-induced writhings model in mice at doses of 100-200 mg/kg. GC/GC-MS analysis of EOs showed that a number of compounds identified in the leaf and root oils were 25 and 31 respectively. The chemical compositions of the oils varied and the major compounds identified in the oils include germacrene D, naphthalene, caryophyllene oxide, α-phellandrene and α-cadinol. The essential root oil did not cause mortality at the highest dose of 5000 mg/kg; hence, its LD50 was estimated to be ⩾5000 mg/kg, p.o. The anti-inflammatory test results showed that the essential root oil caused significant (p < 0.05-0.01) reduction in edema size compared to the negative control group on the carrageenan-induced edema and the results for the analgesic test showed that the essential root oil caused significant (p < 0.05) reduction in number of writhings at 1000 mg/kg compared to the negative control group. It is concluded that root and leaf of this Echinacea species contain volatile oils which varied in their yield and chemical compositions. The essential root oil is non-toxic orally and it demonstrated significant anti-inflammatory and analgesic activities in laboratory animals.

Assessment of the analgesic, anti-inflammatory and sedative effects of the dichloromethanol extract of Schinus molle.

OBJECTIVE: Determination of the active fraction and compounds of the dichloromethanol extract of Schinus molle seeds and evaluation of their biological effects. MATERIALS AND METHODS: Dried seeds of Schinus molle were sequentially extracted in hexane, acetyl acetate and dichloromethane. The dichloromethane extract was separated into two fractions (1 and 2) by column chromatography. Fraction 2 was further separated into its two constituent compounds which were characterized as belonging to the lanosteroid group of compounds. Both factions were tested for their analgesic, anti-inflammatory and sedative effects. RESULTS: The two fractions significantly increased (p<0.05) the tail flick latency though fraction 2 provided better and more long lasting protection against thermal pain. On the other hand, the anti-inflammatory effect of ibuprofen, though inferior to the anti-inflammatory effect of fraction 2 was better than the effects of fraction 1. Fraction 2 significantly (p<0.01) reduced rat paw oedema compared to the saline treatment group throughout the experiments while fraction 2 compared to fraction 1 showed significantly (p<0.01) greater inflammatory effects. On the other hand both fractions lacked significant sedative effects. CONCLUSIONS: Given that fraction 2 had only two constituent compounds (isomasticadienonic and Masticatrienonate), one or both of these compounds should be contributing to the observed analgesic and anti-inflammatory effects.

Effect of breastfeeding during venepuncture in neonates.

BACKGROUND: Evidence suggests that infants feel pain, and painful experiences may lead to subsequent increased pain sensitivity. Owing to concerns regarding the potential adverse effects of pharmacological interventions in newborns, effective alternatives for pain control are being sought. AIM: The Neonatal Infant Pain Scale (NIPS) was used to determine the analgesic effect of breastfeeding during venepuncture. METHODS: The study was of cross-over design where each neonate served as his/her own control. Median pain scores during venepuncture when neonates were being breastfed (BF) were compared with those when neonates were not being breastfed (NBF). The site of venepuncture and number of previous venepunctures were noted. Pain was assessed using NIPS. RESULTS: In all, 38 term neonates (25 male, 13 female) were recruited. Mean (SD) age and weight were 8.42 (8.74) days and 2.89 (0.67) kg, respectively. The median pain score (interquartile range) of the neonates when breastfed was 1.50 (1-2), and 4.00 (2-6) when not breastfed (p=0.0001). The Kruskal-Wallis H-test did not show statistically significant differences between the BF and NBF groups when the number of previous punctures (p=0.57, p=0.27) and site of venepuncture (p=0.71, p=0.77) were considered. CONCLUSION: Using NIPS, it has been demonstrated that breastfeeding is analgesic in neonates during venepuncture and previous venepuncture/s and site of venepuncture do not seem to affect pain scores. Breastfeeding should be the first-choice analgesic during painful procedures in neonates.