Rita A. Dickson

Medicinal plants and finished marketed herbal products used in the treatment of malaria in the Ashanti region, Ghana

ETHNOPHARMACOLOGICAL RELEVANCE Ethnobotanical survey was performed to document medicinal plants employed in the management of malaria in the Bosomtwe and Sekyere East Districts of the Ashanti Region (Ghana), in comparison with the plant ingredients in herbal antimalarial remedies registered by the Ghana Food and Drug Administration. MATERIALS AND METHODS Two hundred and three (203) herbalists from 33 communities within the two districts were interviewed on medicinal plants they use to manage malaria. A literature search was made to determine already documented plants. In addition, 23 finished marketed herbal products indicated for the management of malaria were identified and their labels examined to find out which of the plants mentioned in our survey were listed as ingredients and whether these products are in anyway regulated. RESULTS Ninety-eight (98) species of plants were cited for the management of malaria. In comparison with literature citations, 12 (12.2%) species were reported for the management of malaria for the first time and 20 (20.4%) others for the first time in Ghana. Twenty-three (23) finished marketed herbal antimalarial products examined contained aerial or underground parts of 29 of the plants cited in our survey as ingredients. Twenty-two (22) of these products have been registered by the Ghana Food and Drugs Authority, four (4) of which were included in the recommended herbal medicine list for treating malaria in Ghana. CONCLUSION This study provides new additions to the inventory of medicinal plants used for the management of malaria and reports the commercial availability and regulation of finished marketed labelled herbal products intended for the treatment of malaria in Ghana.

The heavy metal contents of some selected medicinal plants sampled from different geographical locations

Background: The levels of 5 minerals namely; lead, arsenic, mercury, cadmium, and aluminum were assessed in 10 medicinal plants sampled from 5 different geographical locations to determine the effect of location on the plants’ mineral content. Materials and Methods: Atomic absorption spectrophotometry (wet digestion) was used for the analyzes, and content of the minerals per sample was expressed as μg/g. The levels of minerals were compared to their limit specification for herbs and daily total intake of these minerals. A two-way analysis of variance, which tends to look at the effect of the location and the medicinal plant itself on the plants mineral content, was used in the statistical analysis. Results: Lead (Pb) was present in all plant species examined, except Ocimum gratissimum. One plant exceeded the maximum safety limit for lead. Cadmium was also detected in some of the medicinal plant species (44%) whilst majority were below the detection limit (0.002) representing 56%. 40% of the plant species exceeded the limit for cadmium. Mercury and arsenic in all the plant species were below the detection limit (0.001). Significant variation existed in mineral content for the various locations (P ≤ 0.05). Conclusion: The findings generally suggest the variation in mineral levels for the various locations. Thus, our study has shown that same species of medicinal plants, growing in different environments, accumulates different levels of heavy metals.

Chemical Diversity of Lippia multiflora Essential Oils from West Africa

Abstract The essential oil content, composition and the physicochemical properties of Lippia multiflora leaves from twelve different regions in Ghana were characterized in this study. The Ghanaian oils showed a significant variability in their chemical composition and five chemotypes were identified. The oil from Aframso Bridge was yellow with a refractive index (RI) of 1.4853, density (DE) of 0.894 and was dominated by linalool (29%) and germacrene D (28%) with fresh, and slightly medicinal and spicy aroma. Ghanaian samples from Seikwa, Buem Nsuta and Golokwati were characterized by high levels of sesquiterpenes (45–70%). The aroma was medicinal/herbaceous and the color was typically yellow, except the oil from Seikwa which was dark orange-yellow, RI ranging from 1.4920 to 1.5043 and DE 0.893 to 0.93 D. The oils from Nyankpala, Sari, Amantin, Atebubu and Kobre contained high levels of aromatic monoterpenes (p-cymene 14–19%, thymol 30–40%, and thymyl acetate 14–17%). The oils were characterized as spicy and the color ranged from dark yellow (Nyankpala, Sari and Kobre) to yellow (Atebubu and Amantin) (RI 1.4969 to 1.5020, DE 0.9207 to 0.9344). The oil from Ho showed lower levels of aromatic monoterpenes and higher levels of farnesol, the oil was yellow and aroma woody/camphoraceous (1.492 RI, 0.893 D). In contrast, oils from Nsawkaw and Kofiase-Kubesiase were composed of high amounts of 1,8-cineole (43–47%), sabinene (12–15%, respectively), and were light yellow (RI 1.4695 to 1.4712, DE 0.8995 to 0.9002). A cluster analysis was performed for comparison and characterization of L. multiflora oils from Ghana other 33 oils from 10 African countries. The oils from Ghana with these five chemotypes appeared to be the most diverse oils in Sub-Saharan Africa.

Flavonoid glycosides from the stem bark of Margaritaria discoidea demonstrate antibacterial and free radical scavenging activities

One new flavonoid glycoside, along with three known flavonoid glycosides were isolated from the stem bark of Margaritaria discoidea, which is traditionally used in the management of wounds and skin infections in Ghana. The new flavonoid glycoside was elucidated as hydroxygenkwanin‐8‐C‐[α‐rhamnopyranosyl‐(1 → 6)]‐β‐glucopyranoside (1) on the basis of spectroscopic analysis. The isolated compounds demonstrated free‐radical scavenging as well as some level of antibacterial activities. Microorganisms including Staphylococcus aureus are implicated in inhibiting or delaying wound healing. Therefore, any agent capable of reducing or eliminating the microbial load present in a wound as well as decreasing the levels of reactive oxygen species may facilitate the healing process. These findings therefore provide some support to the ethnopharmacological usage of the plant in the management of wounds. Copyright

Antibacterial, anti-inflammatory, and antioxidant effects of the leaves and stem bark of Glyphaea brevis (Spreng) Monachino (Tiliaceae): a comparative study.

Background: Glyphaea brevis (Spreng) Monachino (Tiliaceae) have traditional uses in the management of conditions characterized by infections, inflammatory disorders and oxidative stress. The paper aims to report the comparative data on the leaves and stem bark of Glyphaea brevis with respect to their antibacterial, anti-inflammatory and antioxidant effects. Materials and Methods: The antibacterial effects of the 70% ethanol extracts of the leaves and stem bark were determined using the agar well diffusion and micro dilution assays. The anti-inflammatory activity was assessed using the carrageenan-induced oedema model in 7-day old cockerels. Using the DPPH free radical scavenging, total antioxidant and total phenol content assays, the antioxidant potential of the extract was assessed. Results: The bark extract had the higher antibacterial effect against 6 of the 8 microorganisms used. Noteworthy are its activity against Bacillus subtilis and Enterococcus faecalis with lowest MIC value of 500 μg/mL respectively. In doses of 30, 100 and 300 mg/kg, both extracts reduced the carrageenan-induced oedema in 7-day old cockerels. Based on the ED50 values, both extracts demonstrated similar potencies (ED50 =21.00 mg/kg). The stem bark extract exhibited higher free radical scavenging activity (IC50 = 1.392 mg/mL) compared to the leaf extract (IC50 = 9.509 mg/mL). In the total phenol content, the bark extract showed higher content (15.91 mg/g of dry mass) compared to the leaf extract (2.68 mg/g dry mass). Both extracts demonstrated equal potencies in the total antioxidant capacity determinations (0.60 mg/g dry weight of extract). Conclusions: The results of this work provide scientific evidence for the traditional uses of Glyphaea brevis.

In vitro anti-plasmodial activity of three herbal remedies for malaria in Ghana: Adenia cissampeloides (Planch.) Harms., Termina liaivorensis A. Chev, and Elaeis guineensis Jacq.

Background: Herbal remedies of Adenia cissampeloides, Terminalia ivorensis, and Elaeis guineensis among others have been used in Ghana for the treatment of various ailments including malaria. However, most of these remedies have not been scientifically investigated. Objective: This study, therefore, seeks to investigate the anti-plasmodial activity of these plants. Materials and Methods: The ethanolic extracts of A. cissampeloides stem, T. ivorensis stem bark, and E. guineensis leaves were tested for in vitro anti-plasmodial activity against chloroquine-resistant strains of Plasmodium falciparum. Thin blood films were used to assess the level of parasitemia and growth inhibition of the extracts. Results: The IC 50 of A. cissampeloides, T. ivorensis, and E. guineensis were 8.521, 6.949, and 1.195 μg/ml, respectively, compared to artesunate with IC50 of 0.031 μg/ml. Conclusion: The result of this study appears to confirm the folkloric anti-malarial use these plants.

Chemical constituents from Gouania longipetala and Glyphaea brevis

Five compounds were isolated altogether from the two medicinal plants. Glycerol monotricosanoate (1), palmarumycin BG1 (2) and de-O-methyllasiodiplodin (3) were isolated from Gouania longipetala. In addition, epicatechin (4) and its dimer procyanidin B2 (5) were isolated from the stem bark of Glyphaea brevis. Their structures were elucidated by using spectroscopic experiments. They exhibited radical scavenging and moderate antibacterial effects.

Phytochemical Investigations and Nutritive Potential of Eight Selected Plants from Ghana

This is an article published by Journal of Pharmacy and Nutrition Sciences, 2012, 2, 172-177

Antibacterial, Antioxidant and Anti-inflammatory Properties of Margaritaria discoidea, a Wound Healing Remedy from Ghana

a B S t r a c t Margaritaria discoidea (Baill.) Mull arg. (euphorbiaceae), has folkloric use in the treatment of wounds and skin infections. We report on the antibacterial, antioxidant and anti-inflammatory effects of the leaves and stem bark of Margaritaria discoidea. A 70% ethanolic extract of the various plant parts were tested for antibacterial activity using the agar well diffusion and micro dilution assays. Free radical scavenging, total antioxidant and phenol content were estimated. Using the carrageenan-induced foot pad oedema in chicks, the anti-inflammatory activity of the extract was assessed. The bark extract gave the higher activity with a zone of inhibition of 16.33 ± 0.88 mm against Bacillus subtilis. the Mic’s for the bark extracts ranged from 500 µg/mL to over 1000 µg/mL against the test organisms. However, the leaf extract had no activity against all organisms tested. The leaf and bark extracts demonstrated free radical scavenging activity yielding ic 50 values of 0.0185 and 0.0181 mg/mL respectively. In the total antioxidant assay, ascorbic acid equivalents ranged from 0.49 mg/g in the bark to 0.56 mg/g in the leaf. Both extracts had high phenolic content correlating with their antioxidant activity. The extracts showed significant anti-inflammatory activity. The ED 50 s of the leaf and bark extracts were 12.20 and 8.27 mg/kg body weight respectively. The results were comparable to those of diclofenac and dexamethasone, the reference drugs used in this study. on the basis of the antimicrobial, antioxidant and antiinflammatory activities observed for both extracts, the ethnomedicinal use of the plant in the mamagement of wounds and skin infections is supported.

Acaricidal effect of an isolate from Hoslundia opposita Vahl. against Amblyomma variegatum (Acari: Ixodidae).

Background: Hoslundia opposita Vahl. (Lamiaceae), a common local shrub in Ghana, is traditionally known not only for its pharmacological benefits but also for its insecticidal properties. Its acaricidal property, however, has not been investigated. Objective: To test the acaricidal effects of the crude extract and fractions of H. opposita leaves as well as to isolate and characterize the acaricidal principles. Materials and Methods: The crude methanolic extract, pet. ether, ethyl acetate and aqueous fractions of the leaves of H. opposita were tested against the larvae of the cattle tick, Amblyomma variegatum, using the Larval Packet Test. A bioassay-guided isolation was carried out to identify the acaricidal principle obtained from the ethyl acetate fraction. Results: The active principle was characterised as ursolic acid, a triterpene previously isolated from the leaves of the same plant. The extract and fractions were less potent than the control, malathion (LC50 1.14 × 10-4 mg/ml). Among the plant samples however the crude methanolic extract exhibited the highest effect against the larvae (LC50 5.74 × 10-2 mg/ml), followed by the ethyl acetate fraction (LC50 8.10 × 10-2 mg/ml). Ursolic acid, pet. ether and aqueous fractions however showed weak acaricidal effects with LC50 values of 1.13 mg/ml, 8.96 × 10-1 mg/ml and 1.44 mg/ml, respectively. Conclusion: Ursolic acid was not as potent as the crude methanolic extract and the ethyl acetate fraction from which it was isolated. The overall acaricidal effect of H. opposita may have been due to synergy with other principles having acaricidal properties.