Comparative Study of the Antioxidant Constituents, Activities and the GC-MS Quantification and Identification of Fatty Acids of Four Selected Helichrysum Species.

Helichrysum Mill. (Asteraceae) is a plant genus comprising distinctively of aromatic plants of about 500-600 species. Since most of these plants have not been previously studied, extensive profiling helps to validate their folkloric uses and determine their potential value as sources of plant-derived drug candidates. This study, therefore, aims to investigate the antioxidant activity (DPPH, NO, FRAP); total antioxidant capacity, total phenolic, total flavonoid, and fatty acid compositions of the aqueous acetone extracts from four Helichrysum plants namely, Helichrysum pandurifolium, Helichrysum foetidum, Helichrysum petiolare, and Helichrysum cymocum. The results obtained showed that the H. cymocum extract had the best DPPH radical scavenging activity (IC50 = 11.85 ± 3.20 µg/mL) and H. petiolare extract had the best nitric oxide scavenging activity (IC50 = 20.81 ± 3.73 µg/mL), while H. pandurifolium Schrank extract (0.636 ± 0.005 µg/mL) demonstrated the best ferrous reducing power, all of which are comparable with results from ascorbic acid used as the standard. The IC50 values of the radical scavenging activity ranged from 11.85-41.13 µg/mL (DPPH), 20.81-36.19 µg/mL (NO), and 0.505-0.636 µg/mL (FRAP), for all the plants studied. The H. petiolare has the highest total antioxidant capacity (48.50 ± 1.55 mg/g), highest total phenolic content (54.69 ± 0.23 mg/g), and highest total flavonoid content (56.19 ± 1.01 mg/g) compared with other species. The fatty acid methyl esters were analysed using gas chromatography-mass spectrometry (GC-MS). The results obtained showed variations in the fatty acid composition of the plant extracts, with H. petiolare having the highest saturated fatty acid (SFA) content (7184 µg/g) and polyunsaturated fatty acid (PUFA) content (7005.5 µg/g). In addition, H. foetidum had the highest monounsaturated fatty acid (MUFA) content (1150.3 µg/g), while H. cymocum had the highest PUFA:SFA ratio of 1.202. In conclusion, the findings from this study revealed that H. pandurifolium Schrank, H. foetidum, H. petiolare, and H. cymocum are repositories of natural bioactive compounds with potential health-promoting benefits that need to be investigated, for both their antioxidant activity in a number of disease conditions and for further exploration in drug discovery and development projects.

Medicinal Properties and In Vitro Biological Activities of Selected Helichrysum Species from South Africa: A Review.

The genus Helichrysum Mill comprises hundreds of species that are mostly flowering perennial shrubs. Some of these plants that belong to the Helichrysum species are used in traditional medicine to treat cough, back pain, diabetes, asthma, digestive problems, menstrual pain, chest pain, kidney disorders, skin disorders, wounds, open sores, among other conditions, but, only a few scientific studies are reported in the literature with sufficient information that validates the acclaimed folkloric benefits of these plants. This review, therefore, provides a comprehensive update of the available information on the cytotoxicity, genotoxicity, anti-proliferative, anti-bacterial, anti-fungal, anti-viral, anti-HIV, anti-malarial, anti-ulcerogenic, anti-tyrosinase, anti-inflammatory, and anti-oxidant activities of selected Helichrysum species of interest: H. petiolare, H. cymocum, H. foetidum, and H. pandurifolium Schrank, using scientific databases as well as electronic and print sources. The ethnobotanical and morphological characteristics as well as the phytochemical composition and biological activities of these plants are elucidated. The scientific rationale for their current use is discussed based on the evidence in the literature. This review highlights the putative use of the Helichrysum species as a reliable source of bioactive compounds for the production of standard commercial drugs to treat many ailments, including those reported in folkloric uses. Further research on the many plants in the genus Helichrysum is recommended to explore their economic importance both as edible crops and medicinal botanicals.

In Vitro Evaluation of the Anti-Diabetic Potential of Aqueous Acetone Helichrysum petiolare Extract (AAHPE) with Molecular Docking Relevance in Diabetes Mellitus.

Diabetes mellitus (DM) is a chronic metabolic condition that can lead to significant complications and a high fatality rate worldwide. Efforts are ramping up to find and develop novel α-glucosidase and α-amylase inhibitors that are both effective and potentially safe. Traditional methodologies are being replaced with new techniques that are less complicated and less time demanding; yet, both the experimental and computational strategies are viable and complementary in drug discovery and development. As a result, this study was conducted to investigate the in vitro anti-diabetic potential of aqueous acetone Helichrysum petiolare and B.L Burtt extract (AAHPE) using a 2-NBDG, 2-(N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl) amino)-2-deoxy-d-glucose uptake assay. In addition, we performed molecular docking of the flavonoid constituents identified and quantified by liquid chromatography-mass spectrometry (LC-MS) from AAHPE with the potential to serve as effective and safe α-amylase and α-glucosidase inhibitors, which are important in drug discovery and development. The results showed that AAHPE is a potential inhibitor of both α-amylase and α-glucosidase, with IC50 values of 46.50 ± 6.17 (µg/mL) and 37.81 ± 5.15 (µg/mL), respectively. This is demonstrated by a significant increase in the glucose uptake activity percentage in a concentration-dependent manner compared to the control, with the highest AAHPE concentration of 75 µg/mL of glucose uptake activity being higher than metformin, a standard anti-diabetic drug, in the insulin-resistant HepG2 cell line. The molecular docking results displayed that the constituents strongly bind α-amylase and α-glucosidase while achieving better binding affinities that ranged from ΔG = -7.2 to -9.6 kcal/mol (compared with acarbose ΔG = -6.1 kcal/mol) for α-amylase, and ΔG = -7.3 to -9.0 kcal/mol (compared with acarbose ΔG = -6.3 kcal/mol) for α-glucosidase. This study revealed the potential use of the H. petiolare plant extract and its phytochemicals, which could be explored to develop potent and safe α-amylase and α-glucosidase inhibitors to treat postprandial glycemic levels in diabetic patients.

Attenuation of Endoplasmic Reticulum Stress, Impaired Calcium Homeostasis, and Altered Bioenergetic Functions in MPP+-Exposed SH-SY5Y Cells Pretreated with Rutin.

Parkinson's disease (PD) is a common neurodegenerative disorder that affects approximately 1% of the population over the age of 65 years. While treatment options for PD are limited, reports show that plant-derived bioactive compounds such as rutin possess numerous pharmacological benefits, including antioxidant and antiapoptotic activities. This study aimed to investigate the potential role of rutin in MPP+-treated SH-SY5Y neuroblastoma cells, an established cell model of PD. Our findings reveal increased concentrations of Ca2+ and endoplasmic reticulum (ER) stress as well as impaired mitochondrial membrane potential and bioenergetic status in SH-SY5Y cells treated with MPP+ only. This is demonstrated by a significant reduction in the expression levels of BiP, significantly reduced basal respiration, maximal respiration, and spare respiratory capacity as well as a significant increase in the expression levels of CHOP; however, these effects were significantly attenuated following pretreatment with rutin. Also, rutin significantly improved basal and compensatory glycolysis as a response to an impaired oxidative phosphorylation system triggered by MPP+, characterized by deficient ATP production. In conclusion, our findings provide the first evidence on the ability of rutin to maintain Ca2+ homeostasis, inhibit ER stress, and protect the mitochondria in MPP+-treated SH-SY5Y cells.