Samuel C

Antinutrients are important phytochemicals that also determine the safety of medicinal and nutritional plant parts. The antinutrients of Moringa oleifera and Vernonia amygdalina (bitter leaf) leaves were extracted by soaking, using water, ethanol and hydromethanol (1:1) as solvents. The phytochemical analyses were done both qualitatively and quantitatively (using Spectrophotometer: UV-V15). This study showed that Moringa and bitter leaf contain some antinutritional constituents, including Tannins, Oxalates, Saponins and Alkaloids. Hydromethanol extracted the highest concentration of Tannins (65.91%) from bitter leaf extract. Ethanol extracted the highest concentrations of Oxalates (5.2 x 103 Mg/100g) and Saponins (7,616.84 µg/g) from both medicinal leaves and the highest concentration of Alkaloids from Bitter leaves only. Water extracted the highest concentrations of Alkaloids and Tannins from Moringa leaves only. Generally, ethanol solvent yielded highest crude extraction of antinutrients in the herbs. Therefore, it is also necessary to consider the antinutritional yield of a solvent in the choice of solvents for herbal production.

Studies had shown that hydromethanolic leaf extract of Cnidoscolus aconitifolius (CA) caused dose-dependent antihyperglycaemic or hypoglycaemic effects. Its adverse effects were reportedly lesser compared to some currently used pharmaceuticals. Nuclear Magnetic Resonance (1H NMR-Spectrometry) had been used to analyze the chloroform fraction of this CA extract in order to identify the major and minor phytochemicals responsible for its activities. The presence of the bioactive flavonoids possibly has molecular mechanisms of lowering the diabetic glucose levels and complications. The antidiabetic compounds identified in plant extracts included: isoquercetin, eupafolin, hispidulin, oleanolic acid, β sitosterol and campesterol. These phyto-compounds work through different mechanisms, including the interference of glucose and lipid absorptions, regeneration of pancreatic islets or by increasing the insulin release by beta cells. These phyto-constituents could synergistically lower persistent hyperglycaemia and its complications. The plant leaves of CA are readily available in most residential areas as a vegetable or herb (‘Ogwu-obara’ in Igbo) with reported minimal side effects compared to more costly synthetic antidiabetic drugs. This review calls for the advancement of ethno-pharmaceutical technology in poorer African countries in order to carry out purposeful ethno-pharmacological researches and develop affordable phytotherapy for diabetes.

Evaluation of the nutritive and electrolyte values of edible plants is currently essential for human nutrition and safety. This work assessed the proximate and mineral composition of the leaves of Chaya plant (Cnidoscolus aconitifolius) consumed in Niger Delta Nigeria for medicinal and nutritional purposes. Chaya is commonly known in this southern area of Nigeria as ‘hospital is too far’ or ‘ogwu obala’. The study showed that the dried leaves of the plant contain 47.03 ±1.02% of nitrogen free extract; 33.04± 3.14% of crude fibre; 7.03±0.23% of crude fat; 4.03±0.67% of crude protein, while moisture and ash made up 6.10±1.10% and 3.04±0.32%, respectively. A gram of the dried leaves yielded (in mg) 10±1.2, 20±1.6, 0.01±0.1, 100±5.3, 85±4.32, 18±2.1 and 50±2.3 of Iron, Phosphorus, Sodium, Potassium, Magnesium, Manganese and Calcium, respectively. The energy yield of the leaves was 258±4.5kcal/100 mg. These results suggested the comparative richness of the leaves in fibre, high nitrogen free extract (carbohydrate) and essential minerals. Properly prepared leaves are therefore recommended for daily consumption in order to supplement the recommended daily intake of nutrients and minerals and hence prevent nutritional and electrolyte deficiency disorders.

The leaves of Ocimum gratissimum (OG) and Vernonia amygdalina (VA) had been of medicinal interest mainly due to their respective antioxidant and antihyperglycaemic properties. A daily dose of 0.5gKg-1 body weight aqueous leaf extracts of OG, VA and 50:50 (OG+VA) was orally administered to three different rabbit groups for 28 days, fed ad libitum. The control group was given only 2mlKg-1 of normal saline daily. Fasting blood glucose concentration was monitored with a digital glucometer. From the SPSS (version 15) multivariate analysis (p=.05), results showed that the mean fasting blood glucose concentrations of normal rabbits used was 5.98±0.5 mMolL-1. Only VA lowered fasting blood glucose within 24 hours and maintained the hypoglycaemia for 72 hours; VA potentiated OG after 72 hours and later synergistically lowered fasting blood glucose concentration. This study suggested that VA and (OG+VA) were time-dependent hypoglycaemic: while consumption of VA had acute effect, (OG+VA) could preferably be used for longer prophylaxis of diabetes. Therefore, further researches are recommended on the efficacy of this herbal combination therapy.

The increasing search and utilization of phytochemicals for medicinal purposes necessitated this comparative isolation and characterization of the medicinal constituents in aqueous, hydro-methanolic (1:4, v/v), hydro-ethanolic (1:4, v/v) leaf extracts of Cnidoscolus aconitifolius. The extracts were tested for twelve important medicinal constituents. Alkaloids, tannins, saponins, flavonoids, Salkowski’s test were positive though at different strengths in the three extracts. The presence of combined anthraquinons, saponins, free anthraquinones, terpenes and Liberman’s test appeared weak (33.3%) in aqueous and hydro-ethanolic (1:4, v/v) extracts though totally absent in hydro-methanolic (1:4, v/v) extract. Phlobatanins and cyanogenetic glycosides were absent in the three extracts. Hydromethanolic (1:4, v/v) extract contained at least 66.7% alkaloids, tannins, flavonoids, Salkowski’s test and Kellerkillian’s test and these gave cumulative percent – strength of 300.1% compared to aqueous extract that had 233.3% and hydroethanolic  (1:4, v/v) extract that had 200%. The results implied that hydromethanolic (1:4, v/v) extraction yields more medicinal constituents than aqueous and hydroethanolic (1:4, v/v) extractions. Further analysis of these isolated phytomedicinal constituents are recommended to understand the physiological and therapeutic implications of Cnidoscolus aconitifolius utilizations.