Physicochemical Composition and Antioxidant Activity of Five Gari Processed from Cassava Roots (Manihot esculenta Crantz) Harvested at Two Different Maturity Stages and Two Seasons.

Gari is a partially gelatinized roasted fermented granular white or yellowish product made from storage roots of cassava. It is consumed as fast foods in many countries across the world. Physicochemical composition, particle size, colour, and antioxidant activities of five gari (92/0326, 96/1414, IRAD4115, EN, and AD) processed from fresh storage roots harvested at 12 months after planting (MAP) and 15MAP compared to four (4) commercial gari (M1, M2, M3, and M4) were evaluated. The analytical results revealed that colour value b∗ and particle size varied significantly (p < 0.05) among the gari samples. Bound flavonoid contents were lower than free flavonoids (3.93 to 10.50 mgQE/100 g and 2.40 to 8.85 mgQE/100 g, respectively). Fourier transform infrared confirmed the functional groups in all gari samples. The antioxidant activity of the bound phenolics showed significantly (p < 0.05) higher DPPH scavenging ability than free phenolics (gari M2: 2.70 µgTE/g). Similarly, the bound phenolics showed significant (p < 0.05) variation of HRSA scavenging activity (0.18-35.09 µgTE/g). However, the best HRSA scavenging activity was found with bound phenolics of gari 96/1414, whereas HRSA scavenging activity was not detected in gari 92/0326, 96/1414, and AD. The value of ABTS scavenging activity of gari varied significantly (p < 0.05) from 20.60 to 30.17 µgTE/g and from 20.70 to 34.39 for free and bound phenolics, respectively, while free phenolics showed higher FRAP value (7.97 mgTE/g) than the bound phenolics (4.59 mgTE/g). Additionally, phenolics and antioxidant activities showed significantly (p < 0.05) a positive correlation. The present study has provided an insight into the physicochemical composition, bioactive compounds, and antioxidant activities of various gari processed at different season and maturity period of harvesting. It reveals that consumers of cassava gari can get health benefits apart from the nutritional values.

Hydromethanolic Root Extract of Gnidia Kraussiana Demonstrates Anti-Inflammatory Effect Through Anti-Oxidant Activity Enhancement in a Rodent Model of Gout.

Gout is a metabolic arthritis that originates from increased accumulation of monosodium urate (MSU) crystals in joints. This work aimed to evaluate the antioxidant and anti-inflammatory activities of the hydromethanolic extract of Gnidia kraussiana (HEGK) using model of Gouty arthritis on mice. The total polyphenol, flavonoid, tannin content and the antioxidant activity of HEGK were also evaluated. MSU-injected mice were treated daily for 3 days with HEGK (25, 50 and 100 mg/kg). Indomethacin and colchicin were used as reference drugs. Paw oedema and body temperature were measured at different time intervals post-injection. Malondialdehyde, acid phosphatase, ß-Galactosidase, catalase, superoxide dismutase and glutathione levels were evaluated. HEGK is rich in polyphenol (129.93 mg/100 g), flavonoid (67.78 mg/100 g) and tannin conferring it a high antioxidant activity. Acute oral toxicity of HEGK resulted in LD50 greater than 2000 mg/kg. Oral administration of HEGK induced a significant decrease in the oedema of legs injected with urate crystals and reduced the release of acid phosphatase and ß-Galactosidase. A model of oxidative damage was successfully established, revealing a significant increase in malondialdehyde and inhibition of antioxidants, including superoxide dismutase, catalase and glutathione activity. Thus, HEGK can actively inhibit the effect of inflammatory mediators in gouty arthritis.

Antibacterial and antioxidant activities and phytochemical composition of Stereospermum kunthianum root bark.

A new glycoiridoid (1) together with seven (7) known compounds were isolated from the methanol crude extract of the root bark of Stereospermum kunthianum using chromatography methods. Their structures were elucidated using HR-ESI-MS, 1 D- & 2 D-NMR spectroscopies in comparison with previous literature. The antioxidant activity was investigated by using FRAP, DPPH, ABTS and HRSA methods while the antibacterial activity was assays on Escherichia coli (ATCC25922) and Salmonella typhimurium (ATCC14028) strains. The results showed that the isolated compounds had significantly (p < 0.01) high radical scavenging (IC50) and reducing power activity. All bacteria strains showed important minimal inhibitory concentration activity against isolated compounds started at 5 mg/mL with an inhibition zone of 6 mm. Thus, the isolated compounds in S. kunthianum justify the use of the plant in traditional medicine for the treatment of various diseases in humans. These isolated compounds can be used for formulation of new drug discovery to treat infectious diseases.

Polyphenols in cassava leaves (Manihot esculenta Crantz) and their stability in antioxidant potential after in vitro gastrointestinal digestion.

The study was carried out to assess the effect of variety on polyphenols in cassava leaves and their stability in antioxidant activity before and after in vitro gastrointestinal digestion. The results showed that individual and total polyphenols content (TPC) and antioxidant activity of bound, free and bioaccessible polyphenols were significantly (p < 0.05) influenced by variety at harvesting maturity. The bound polyphenols had lower TPC (5.00-19.16 mg GAE/g) than free (39.16-89.61 mg GAE/g) throughout harvesting maturity. The polyphenols were strongly affected after in vitro digestion, however, salicylic, syringic and benzoic acids are the most bioaccessible. The free polyphenols of variety IRAD4115 had the highest value of FRAP (35.17 µg TE/g) at 12 months after planting (MAP), while, bound polyphenols showed the lowest DPPH (6.59 µg TE/g, variety EN at 12MAP). The antioxidant activity value evaluated by DPPH method was decreased significantly after in vitro gastrointestinal digestion. However, there was no significant difference between antioxidant activity of bioaccessible polyphenols (77.71 µg TE/g) and methanolic polyphenols (79.17 µg TE/g) assessed by FRAP method. These findings showed the stability of antioxidant potential of polyphenols in cassava leaves harvested at different periods after in vitro digestion. Thus cassava leaves harvested at appropriate maturity can be used as ingredient of functional food for nutraceutical benefits.

Effect of Harvest Period on the Proximate Composition and Functional and Sensory Properties of Gari Produced from Local and Improved Cassava (Manihot esculenta) Varieties.

This study is aimed at evaluating the proximate composition and functional and sensory characteristics of gari obtained from five cassava varieties (EN, AD, TMS92/0326, TMS96/1414, and IRAD4115). These cassavas were harvested during the dry season 12 months after planting (12MAP) and in the rainy season (15MAP). Results showed that the characteristics of gari varied significantly (p < 0.05) with the variety and the harvest period. Gari from EN cassava harvested at 12MAP had the highest total carbohydrates (78.07% dry weight), starch (61%), and proteins content, while gari from TMS 96/1414 variety (12MAP) had high amino acids (10.25 mg/g) and phenolic compounds (9.31 mg/g) content. The gari from IRAD4115 had the highest value of ash content (20.62 mg/g) at 12MAP. The soluble sugar content was high in the gari from cassava harvested at 12MAP while free cyanide reduced significantly in gari from cassava harvested at 12MAP. The water absorption capacity, swelling power, and bulk density were significantly (p < 0.05) high in the gari from EN cassava variety at 12MAP. Compared to commercial gari (3.30), gari from EN local cassava had the best overall acceptability (4.35) followed by those obtained from TMS92/0326 and TMS92/1414 varieties, respectively.