Opeoluwa O. Oyedeji

Cymbopogon species; ethnopharmacology, phytochemistry and the pharmacological importance.

Cymbopogon genus is a member of the family of Gramineae which are herbs known worldwide for their high essential oil content. They are widely distributed across all continents where they are used for various purposes. The commercial and medicinal uses of the various species of Cymbopogon are well documented. Ethnopharmacology evidence shows that they possess a wide array of properties that justifies their use for pest control, in cosmetics and as anti-inflammation agents. These plants may also hold promise as potent anti-tumor and chemopreventive drugs. The chemo-types from this genus have been used as biomarkers for their identification and classification. Pharmacological applications of Cymbopogon citratus are well exploited, though studies show that other species may also useful pharmaceutically. Hence this literature review intends to discuss these species and explore their potential economic importance.

Chemical composition and anti-inflammatory activities of the essential oils from Acacia mearnsii de Wild

The volatile oils of the leaves and the stem bark of Acacia mearnsii de Wild obtained by hydro-distillation were analysed by gas chromatography–mass spectrometry. A total of 20, 38, 29 and 38 components accounted for 93.8%, 92.1%, 78.5% and 90.9% of the total oils of the fresh, dry leaves and fresh, dry stem bark, respectively. The major components of the oil were octadecyl alcohol (25.5%) and phytol (10.5%); cis-verbenol (29.5%); phytol (10.1%) and phytol (23.4%) for the fresh leaves, dried leaves, fresh stem, dry stem bark, respectively. Oral administration of essential oils at a dose of 2% showed significant (p < 0.05) anti-inflammatory properties in the albumin-induced test model in rats. Oils from the fresh leaves and dry stems inhibited inflammation beyond 4 h post treatment. The potent anti-inflammatory activity of essential oils of A. mearnsii hereby confirmed its traditional use in treating various inflammatory diseases.

Anti-Inflammatory and Membrane-Stabilizing Properties of Two Semisynthetic Derivatives of Oleanolic Acid

Acetylation and methylation semisynthesis of oleanolic acid (OA) isolated from Syzygium aromaticum L. yielded two compounds: 3-acetoxyoleanolic acid (3-AOA) and 3-acetoxy, 28-methylester oleanolic acid (3-A,28-MOA). Anti-inflammatory properties of these compounds were assessed using the serotonin and fresh egg albumin-induced inflammatory test models in male Wistar rats weighing 250–300 g. Furthermore, erythrocyte membrane-stabilizing property of these compounds was evaluated in the heat- and hypotonicity-induced in vitro hemolysis test models. The two semisynthetic compounds significantly (p < 0.05) inhibited albumin-induced inflammation better than OA and indomethacin from 1–5 h post administration. Both compounds were membrane stabilizing in heat-induced hemolysis test while only 3-AOA showed membrane-stabilizing effects in a hypotonic milieu. Semisynthesis of OA yielded two compounds which had better in vivo anti-inflammatory and in vitro membrane-stabilizing properties.

Compositional Variations and Antibacterial Activities of the Essential Oils of three Melaleuca Species from South Africa

Abstract The leaf oils of three Melaleuca species, M. bracteata var. revolution gold, M. bracteata var. revolution green and M. trichostachya var. compacta from South Africa have been studied for their volatile constituents and bacterial activities. Isolation of the oils were performed through hydrodistillation using a Clevenger apparatus for 4h. Redistillation after 7 h was carried out on the extracted plant material via hydrodistillation method for another 3 h. The compositions of the first distillates were at variance with the second distillates especially with M. trichostachya var. compacta oils. A schematic postulate has been proposed for the rearrangement transformation of some compounds. The chemical profile of oils of M. trichostachya var. compacta has been reported for the first time. The results of zone of inhibition (ZI) and minimum inhibition concentration (MIC) activities of the 6 oils against an array of 12 bacteria pathogens are also reported.

Semisynthesis of Derivatives of Oleanolic Acid from Syzygium aromaticum and Their Antinociceptive and Anti-Inflammatory Properties

Oleanolic acid is a pentacyclic triterpenoid compound widely found in plants and well known for its medicinal properties. Oleanolic acid (OA) was isolated from the ethyl acetate extract of Syzygium aromaticum flower buds. Semisynthesis afforded both acetate and ester derivatives. The derived compounds were monitored with thin layer chromatography and confirmed with nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), Fourier infrared (FT-IR) spectroscopy, and melting point (Mp). All these compounds were evaluated for their analgesic and anti-inflammatory properties at a dose of 40 mg/kg. Significant analgesic and anti-inflammatory effects were noted for all OA-derived compounds. In the formalin-induced pain test, the derivatives showed better analgesic effects compared to their precursor, whereas, in the tale flick test, oleanolic acid proved to be superior in analgesic effects compared to all its derivatives with the exception of the acetyl derivative. Acute inflammatory tests showed that acetyl derivatives possessed better anti-inflammatory activity compared to the other compounds. In conclusion, semisynthesis of oleanolic acid yielded several derivatives with improved solubility and enhanced analgesic and anti-inflammatory properties.

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.

Biosynthesis of silver nanoparticles from Acacia mearnsii De Wild stem bark and its antinociceptive properties

ABSTRACT The biosynthesis of silver nanoparticles (Ag-NPs) using the hydrosol extract of the dry stem bark of Acacia mearnsii as reducing and capping agents, and their antinociceptive properties are hereby reported. By varying the temperature and reaction time, the temporal evolution of the optical and morphological properties of the as-synthesized material was investigated. The NPs were characterized by UV–visible absorption spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS) and x-ray diffractometry (XRD) The optical analyses show that the position of the maximum surface plasmon resonance (SPR) peak is red-shifted as the reaction temperature decreased. The TEM micrographs show that the as-synthesized Ag-NPs are spherical while the X-ray diffraction shows that the material is highly crystalline with face-centered cubic structures. The anti-inflammatory efficacy, analyzed by the formalin model, indicates that the as-synthesized Ag-NPs are very effective, with an inhibition rate of about 76%. GRAPHICAL ABSTRACT

Synthesis of Silver Nanoparticles Using Buchu Plant Extracts and Their Analgesic Properties

We herein report for the first time the synthesis and analgesic properties of silver nanoparticles (Ag-NPs) using buchu plant extract. The as-synthesised Ag-NPs at different temperatures were characterised by UV-Vis spectroscopy, Fourier transform infra-red spectroscopy (FTIR) and transmission transform microscopy (TEM) to confirm the formation of silver nanoparticles. Phytochemical screening of the ethanolic extract revealed the presence of glycosides, proteins, tannins, alkaloids, flavonoids and saponins. The absorption spectra showed that the synthesis is temperature and time dependent. The TEM analysis showed that the as-synthesised Ag-NPs are polydispersed and spherical in shape with average particle diameter of 19.95 ± 7.76 nm while the FTIR results confirmed the reduction and capping of the as-synthesised Ag-NPs by the phytochemicals present in the ethanolic extract. The analgesic study indicated that the combined effect of the plant extract and Ag-NPs is more effective in pain management than both the aspirin drug and the extract alone.

Evaluation of Trace Metal Profile in Cymbopogon validus and Hyparrhenia hirta Used as Traditional Herbs from Environmentally Diverse Region of Komga, South Africa

FAAS was used for the analysis of trace metals in fresh and dry plant parts of Cymbopogon validus and Hyparrhenia hirta species with the aim of determining the trace metals concentrations in selected traditional plants consumed in Eastern Cape, South Africa. The trace metal concentration (mg/kg) in the samples of dry Cymbopogon validus leaves (DCVL) showed Cu of 12.40 ± 1.000; Zn of 2.42 ± 0.401; Fe of 2.50 ± 0.410; Mn of 1.31 ± 0.210; Pb of 3.36 ± 0.401 mg/kg, while the samples of fresh Hyparrhenia hirta flowers (FHHF) gave Cu of 9.77 ± 0.610; Zn of 0.70 ± 0.200; Fe of 2.11 ± 0.200; Mn of 1.15 ± 0.080; Pb of 3.15 ± 0.100 mg/kg. Abundance of metal concentrations follows the order: Cu > Fe > Pb > Mn > Zn in the flower samples of Cymbopogon validus and Hyparrhenia hirta species. The concentrations of trace metals in both plant parts were below the permissible limits (PL) set by WHO. It is suggested that pharmacovigilance be carried out periodically to improve the quality, safety, and efficiency of various herbal products.

The effect of Cordia platythyrsa on various experimental models of pain and carrageenan induced inflammation

Only one study has reported on the medicinal properties of Cordia platythyrsa ( C. platythyrsa ) though it is used in African traditional medicine for treatment of fever and pain. The current study aimed at investigating the analgesic and anti-inflammatory properties of C. platythyrsa using various animal models: writhing test, tail flick, thermal hyperalgesia, mechanically induced-pain, formalin-induced pain and carrageenan-induced inflammation tests. Like aspirin, the two doses of plant extracts used inhibited acetic acid-induced pain though these effects were weaker than the effects of morphine. Although, the plant extract significantly (p<0.01) inhibited thermal pain, its effects were less significant compared to morphine. Celecoxib (10 mg/kg) and plant extract (100 mg/kg) significantly inhibited thermal hyperalgesia compared to indomethacin. On the other hand, both doses of plant extract significantly increased mechanical pain thresholds 30 and 90 min post treatment. The plant extract (150 mg/kg) inhibited both the neurogenic and inflammatory pain phases of formalin-induced pain as well as carrageenan-induced inflammation. This study is the first to show that C. platythyrsa has analgesic and anti-inflammatory properties. Keywords: Analgesia, pain, writhing, formalin, thermal hyperalgia African Journal of Biotechnology , Vol. 13(2), pp. 343-348, 8 January, 2014