RESUMO
With the advent of modern technology, advancements in processing and storage techniques, and increasing medical knowledge, people are becoming aware of deterioration in the quality of medicinal products due to storage methods and time. In most cases, herbal products are not consumed immediately after production; as such, improper storage can result in physical, chemical, and microbiological changes. The study evaluated the effect of storage methods and time on the quality of oil extracted from Phyllanthus amarus Schumach and Annona muricata Linn and assessed their antidiabetic and antioxidative effects. Plants were air-dried, pulverized, and then subjected to Soxhlet extraction in petroleum ether. The oil was evaluated for phytochemical constituents and the effects of time and storage methods on its physicochemical properties. Characterization of the oil was done by spectroscopic techniques. Oils from both plants contained tannins, flavonoids, alkaloids, steroids, glycosides, terpenoids, phlobotannins, resins, reducing sugar, phenols, and saponins in different proportions. The oil from A. muricata had higher phenolic (3.11 ± 0.31 mg GAE/g), flavonoid (11.82 ± 0.08 mg QUE/g), alkaloid (16.37 ± 0.56 mg APE/g), and tannin (7.13 ± 0.47 mg CE/g) contents than the oil from P. amarus, which had 0.54 ± 0.08 mg GAE/g, 7.83 ± 0.13 mg QUE/g, 9.87 ± 0.15 mg APE, and 3.16 ± 0.12 mg CE/g for total phenolic, flavonoids, alkaloids, and tannins, respectively. Initial acid, iodine, peroxide, and saponification values recorded for P. amarus were 5.63 ± 0.82 mg KOH/g, 97.17 ±0.53 Wijis, 9.31 ± 0.15 mEq/kg, and 116.11 ± 0.74 mg KOH/g, respectively, significantly different from those of A. muricata , which had values of 1.17 ± 0.08 mg KOH, 76.23 ± 0.03 Wijis, 6.75 ± 0.47 mEq/kg, and 193.31 ± 0.52 mg KOH/g, respectively. FT-IR characterization of the oils revealed the presence of carboxylic acid, alkyl, alkene, alkane, haloalkane, aldehyde, aromatic amine, α-unsaturated and ß-unsaturated esters, and phenol functional groups. P. amarus oil inhibited α-amylase (IC50 0.17 ± 0.03 mg/ml), α-glucosidase (IC50 0.64 ± 0.03 mg/ml), and xanthine oxidase (0.70 ± 0.01 mg/ml) to a greater extent than A. muricata oil, with IC50 values of 0.43 ± 0.05 mg/ml (α-amylase), 2.25 ± 0.31 mg/ml (α-glucosidase), and 0.78 ± 0.07 mg/ml (xanthine oxidase). This study showed that oils from the tested plants have low rancidity with a moderate shelf life. The extracts contained essential phytoconstituents that significantly inhibited α-glucosidase and xanthine oxidase. These effects of the oil indicate their potential to prevent diabetes, gout, and oxidative stress. Consequently, the supply of P. amarus and A. muricata in homemade diets is strongly encouraged for healthy living.
RESUMO
In this work, CuO nanoparticles (NPs) were prepared from the aqueous extracts of Solanum macrocarpon fruit by using the conventional heating (CuO(h) NPs) and microwave irradiation (CuO(m) NPs) methods. The synthesized nanoparticles were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The SEM analysis revealed that the CuO NPs from both routes contained essentially smooth surfaces, and displayed some degree of agglomeration. The TEM analysis confirmed some spherical morphology with mean particle sizes of 35.60 ± 6.24 nm and 47.14 ± 6.18 nm for the CuO(h) and CuO(m) NPs respectively. While the CuO(m) NPs possessed a single-phase consistent with the face cantered cubic structure of copper oxide, the CuO(h) NPs showed some extra peaks attributed to Cu2O NPs as secondary phase. Electrochemical studies were conducted in order to evaluate the electrochemical properties of the NPs. The responses of a gold screen-printed electrode surface treated with both NPs showed that their redox behaviours on (Fe(CN)6)3-/4- probe and KCl electrolytes vary significantly. In (Fe(CN)6)3-/4- probe, the SPAuE/CuO(h) showed enhanced electrochemical response relative to the bare, while the SPAuE/CuO(m) showed a lower current response than the bare. However, in the KCl electrolye, the SPAuE/CuO(h) and SPAuE/CuO(m) were highly electroactive and demonstrated peak current magnitude that was about 26.5 and 83.38 times higher than that of the bare. In this KCl medium, the magnitude of the oxidation peak current of Cu2+ for SPAuE/CuO(m) was about 3 times higher than that of SPAuE/CuO(h). The percentage contraction in redox coordinates between the 1st and 10th scans in both electrodes were 3.88 and 19.28% for SPAuE/CuO(h) and SPAuE/CuO(m) respectively. Thus, the choice of green synthesis route could be exploited in different fields where green NPs is desired.
