ABSTRACT

The unascertained claims of the flower, seed, leaf, stem bark and root bark of Moringa oleifera as sources of antioxidants, anti-cancer, anti-inflammatory agent, anti-diabetic, anti-bacterial, anti-coagulant, nutritional, and some chemical functionalities are receiving serious attention among scientists as potential components in human nutrition, general health and industrial raw materials. For safety reasons to the consuming public, before introduction of the plant into the health sector, some of the claims must be screened for scientific proofs.  The plant parts were harvested from a single healthy plant. The samples were washed, shade-dried, ground and used for analyses. Structured questionnaire was used to obtain demographic information from purposive population on the use, perceived efficacy, and safety of the plant parts. Proximate and mineral composition and phytochemicals status was determined.  Antioxidant activity of ethanol extracts of the samples were determined on standard free radicals; DPPH, H₂O₂, NO and ABTS and FRAP against ascorbic acid (AA) as standard using standard analytical methods.  The response surface analysis (RSA) was used to optimize some biomarkers (Y_n) and histology of streptozotocin (STZ) induced Type-2 diabetes Albino rats treated with ethanol extract of the moringa leaf using concentration (X₁), exposure time (X₂) to the extract and gender of the rat (X₃) as independent variables to assess safety of the plant extracts. Demographic study revealed that 100% of the respondents had some idea of and used moringa plant for different purposes. 194(64.67%) of the respondents were of the female gender, which indicated a higher enthusiasm to participate in the study than the male counterpart 106(35%). The 36-45 years’ age group, 180(43.33%) of the respondents constituted the group that used the plant in traditional medicine. Efficacy 68(22.70%), 79(26.3%) availability, affordability 90(30.00%), poor orthodox medical services 51(17.00%) were factors which induced prevalence of use of the plat. Demographic study of the studied population sample provided human insight into perceived efficacy and safety of the plant. Result of proximate composition of parts of the plant showed 4.48, 3.35, 3.36, 3.37 and 4.19% moisture content in the flower, seed, leaf, stem bark and root bark respectively. Ash content of 6.45, 7.27, 7.25, 7.26 and 7.25% was observed in the flower, seed, leaf, stem bark and root bark respectively. Fiber content of the flower, seed, leaf, stem bark and root bark were 2.62, 2.39, 7.45, 2.45, 2.31% respectively. Crude fat content of 11.10, 10.28, 7.89, 10.31 and 10.33% was observed in the flower, seed, leaf, stem bark and root bark, respectively. Protein content of 9.45, 10.58, 9.81, 9.81 and 10.65% was observed btained in the flower, seed, leaf, stem bark and root bark respectively. Carbohydrate content was 55.43, 57.59, 55.87, 55.87, 56.80% in flower, seed, and leaf, stem bark and root bark respectively, while the energy value was 386.75, 365.17, 361.37, 384.73 and 367.26 Kcal/100g in the flower, seed, leaf, stem bark and root bark respectively. Calcium content of 477.93, 2013.60, 684.46, 481.00±1.00 and 1179.0 mg/100g was observed in the flower, seed, leaf, stem bark and root bark, respectively. Magnesium content was 207.75, 320.95, 343.15, 245.00, 587.00 mg/100g respectively. Potassium in flower, seed, leaf, stem bark and root bark were 470.77, 1849.72, 557.08, 401.25, 1641.0 mg/100g prospectively. Sodium content was 191.0, 920.52, 203.0, 201.43, and 821.35 mg/100g in flower, seed, leaf, stem bark and root bark samples, respectively. The concentration of Zn in the flower, seed, leaf, stem bark and root bark of the plant was 0.81, 0.95, 0.923, 1.191, 1.285 mg/100 g, respectively. Iron content of 18.245, 19.349, 13.603, 17.121, and 14.958 mg/100 g was observed in the flower, seed, leaf, stem bark and root bark, respectively. Selenium was present in traces; 0.011, 0.001, 0.003, 0.015, and 0.006 ppm in flower, seed, leaf, stem bark and root bark respectively. Qualitative screening of the plant parts showed varying presence of alkaloids, saponins, tannins, flavonoids, deoxy sugar, cardiac glycoside, steroids, and phenols. The free radical scavenging activity of the extracts on DPPH, H₂O₂, NO, and ABTS and FRAP were significant (p<0.05). Extract of the flower, seed, leaf, stem, and root barks on DPPH exhibited reducing power (IC₅₀) of 55.12, 57.71, 59.80, 65.15 and 65.01, H₂O₂ (67.80, 62.00, 40.99, 50.72, 62.03), NO (60.35, 61.01, 64.23, 68.09, and 71.62), ABTS (62.19, 58.92, 62.57, 63.07), AAE/g and FRAP (51.99, 46.54, 21.33, 21.41, and 59.26 AAE/gdw of sample, respectively against 40.56 AA. Correlation of reducing power of the free radicals was significant (p<0.05; r>90%). Carotenoid content in the leaf was 13-Cis β-carotene, (19.34%), trans β-carotene (22.67%), 9-cis β-carotene (24.40%) traces was obtained in the stem bark, none was detected in the flower, seed, and the root bark of the plant.  The mathematical models of the blood glucose, body weight, red blood count, glutathione, malondialdehyde, superoxide dismutase (SOD), were not statistically significant (p>0.05), the model for weight of kidneys was significant (p<0.05) however, all the models exhibited concentration-, exposure-time and gender was not a good predictor. The 3D response surface plots showed some levels of influence of all the variables on the parameters. Optimization analysis on the response surface data showed that 46% concentration of the plant extract, 42 days of exposure time, and gender of 1.09 respectively produced blood glucose of 152 mg/l, body weight of 170 g, red blood count of 84%, glutathione level of 5.7 mg/L, malondialdehyde of level of 57 Umol/g, SOD of 241.88 mg/l and kidney weight of 2.4 g at 76.9 level of desirability. Histology of the liver and the kidneys showed concentration-exposure tme trend on the restoration of the biomarkers. The observations in demographic study, proximate composition, inhibition activity and antioxidant activities, response surface analysis of the bioactive data and carotenoid content in the leaf of the plant indicated that the plant extract was healing and safe in mammalian subjects. Therefore, the plant may retain some of the claims of efficacy and safety at the concentration used in the study. More work on the topic is recommended before it can be fully introduced into the health system.