Effect of extraction solvents and thermal drying methods on bioactive compounds and antioxidant properties of Catharanthus roseus (L.) G. Don (Patricia White cultivar)

Solvent Effects on the Phenolic Compounds and Antioxidant Activity Associated with Camellia polyodonta Flower Extracts

Camellia polyodonta flowers contain limited information available regarding the composition of their bioactive compounds and activity. The objective of this study was to identify phenolic compounds and investigate the effect of different solvents (ethanol and methanol) on the phenolic content and antioxidant activity in C. polyodonta flowers. The analysis using UPLC-Q-TOF-MS/MS revealed the presence of 105 phytochemicals and the most common compounds were flavonols, procyanidins, and ellagitannins. Interestingly, flavonol triglycosides were identified for the first time in these flowers. The study demonstrated that the concentration of the solvent had a significant impact on the total phenolic compound (TPC), total flavonoid compound (TFC), and total proanthocyanidin content (TPAC). The TPC, TFC, and TPAC showed a remarkable increase with the increasing concentration of the solvent, reaching their maximum levels (138.23 mg GAE/g DW, 421.62 mg RE/g DW, 60.77 mg PB2E/g DW) at 70% ethanol. However, the total anthocyanin content reached its maximum at low concentrations (0.49 mg CGE/g DW). Similar trends were observed in the antioxidant activity, as measured by the DPPH· assay (DPPH radical scavenging activity), ABTS·+ assay (ABTS radical cation scavenging activity), and FRAP assay (Ferric reducing antioxidant power). The maximum antioxidant activity was observed at 100% solvents and 70% methanol. Among the 14 individual phenolic compounds, 70% methanol yielded the highest content for 8 (cyanidin-3-O-glucoside, procyanidin B2, procyanidin B4, epicatechin, rutin, kaempferol-3-O-rutinoside, astragaline and quercitrin) out of the 14 compounds. Additionally, it was found that epicatechin was the most abundant phenolic compound, accounting for approximately 20339.37 μg/g DW. Based on these findings, it can be concluded that 70% methanol is the most effective solvent for extracting polyphenols from C. polyodonta flowers. These results provided chemical information and potential antioxidant value for further research in C. polyodonta flowers.

Comparative evaluation of ethylene oxide, electron beam and gamma irradiation treatments on commonly cultivated red chilli cultivars (Kunri and Hybrid) of Sindh, Pakistan

Chillies are considered a universal ingredient for imparting flavor and pungency to foods. Pakistan stood in the top twenty countries worldwide by producing 82 thousand Tons of chillies during 2022-23. Chilli fungal contamination and aflatoxin production during drying is a common problem during post-harvest process. Gasses treatment and Ionizing radiations are efficient methods for reducing toxigenic and pathogenic microbial growth in food items. The current study was designed to compare the effects of ethylene oxide (ETO), gamma (GB) & electron beam (EB) treatments on two red chilli local cultivars (Kunri and Hybrid) of Pakistan. After treatment, the chilli samples were analyzed for aflatoxins, physicochemical, quality & safety attributes. All results were subjected to Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), dendrogram and ANOVA to check the correlations, grouping and level of significance within the varieties and treatments. The results showed that moisture and water activity mainly designated PC-2 directions and are slightly positively correlated. Conversely, both fat and proteins have a negative correlation with moisture, ash and water activity. Besides, carotenoids and ABTS assay mainly designated PC-2 directions and are slightly positively correlated. Color, flavonoids and TPC also possess positive correlations among them. ETO depicts effectiveness in the reduction of E. coli but is not effective in saving antioxidant potential such as total flavonoids. Similarly, gamma irradiations showed strong reduction trends in fungal and pathogenic count, however same trend was observed in ascorbic acid too. Besides, the electron beam with dosage levels of 12 and 15 kGy has shown effectiveness against Aspergillus spp., aflatoxins and pathogenic microbial load in addition to saving antioxidant potential (phenolics and flavonoids), physicochemical parameters and color values compared to other applied methods especially in Kunri variety. It was evident from the research that varietal combination in addition to applied treatment must be specially considered while designing a treatment for chillies.

Assessment and comparison of phytochemicals and antioxidant properties from various parts of the Australian maroon bush (Scaevola spinescens)

Scaevola spinescens is endemic to Australia and traditionally used as a medicinal plant. While its bioactive compounds have been studied, their concentrations in different parts of the plant have not been reported. This study compared total phenolic content (TPC), flavonoids, saponins and antioxidant properties, as well as major individual phytochemical compounds in the whole root, root bark, root wood, whole stem, stem bark, stem wood, and leaf of S. spinescens. The results showed the leaf had significantly highest concentrations of TPC followed by the root bark and stem bark (47.34, 12.24 and 10.20 mg GAE/g, respectively). Flavonoids concentrations were also significantly higher in the leaf compared to the root bark and stem bark (20.95, 6.22 and 4.19 mg CE/g, respectively). For saponins, the root bark contained significantly highest concentrations (112.58 mg EE/g). Luteolin 7-glucoside was isolated and identified in the leaf of S. spinescens. Eight major compounds were identified with the leaf displaying the highest diversity of major compounds, and in higher concentrations, compared to the other plant constituents. As the leaf and root bark contained the highest concentrations of phytochemicals, these plant parts are recommended as starting material for future studies, to further isolate and identify the major compounds from S. spinescens and investigate their biological properties for use in pharmaceutical and food applications.

Ethnopharmacology, Biological Activity and Phytochemistry of Scaevola spinescens

Scaevola spinescens is endemic to Australia and has traditionally been used by Aboriginal and Torres Strait Islander communities to treat a variety of conditions including colds, flu, fever, stomach pain, urinary disorders, sores, tinea, leprosy, and cancer. Extracts prepared from S. spinescens are non-toxic and have been linked with various medicinal properties including antiviral, antibacterial, anti-inflammatory, and anticancer activities. These studies support the ethnopharmacological use of S. spinescens by Indigenous peoples of Australia and highlight the need for further investigations on the plant for potential use in pharmaceutical and food applications. This review provides a comprehensive, up-to-date review of the literature on S. spinescens focusing on the traditional use, medicinal properties, phytochemicals, and factors that affect their composition during pre-treatment and extraction, as well as providing a framework for future studies of the plant.

Phytochemicals Derived from Catharanthus roseus and Their Health Benefits

Catharanthus roseus (C. roseus) is an important medicinal plant distributed in many countries. It has attracted increasing attention due to it being shown to possess a range of phytochemicals with various biological activities such as antioxidant, antibacterial, antifungal, antidiabetic and anticancer properties. Remarkably, vinblastine and vincristine isolated from this plant were the first plant-derived anticancer agents deployed for clinical use. Recently, new isolated indole alkaloids from this plant including catharoseumine, 14′,15′-didehydrocyclovinblastine, 17-deacetoxycyclovinblastine and 17-deacetoxyvinamidine effectively inhibited human cancer cell lines in vitro. Moreover, vindoline, vindolidine, vindolicine and vindolinine isolated from C. roseus leaf exhibited in vitro antidiabetic property. These findings strongly indicate that this plant is still a promising source of bioactive compounds, which should be further investigated. This paper provides an overview of the traditional use and phytochemical profiles of C. roseus, and summarises updated techniques of the preparation of dried material, extraction and isolation of bioactive compounds from this plant. In addition, purported health benefits of the extracts and bioactive compounds derived from this plant were also addressed to support their potential as therapeutic agents.

In vitro antioxidant and antimicrobial potential of Sterculia urens Roxb. root extract and its bioactive phytoconstituents evaluation

Background

The plant Sterculia urens Roxb. of Malvaceae family is comparatively understudied. Genus Sterculia is widely recognized by its phytomedicinal and ethnomedicinal attributes. The study is aimed to evaluate the qualitative analysis, Fourier transform infrared (FT-IR), thin layer chromatography (TLC), total phenolic content (TPC), antioxidant and antimicrobial activities of the crude hydro-methanolic extract of S. urens root.

Results

The antioxidant activity, antimicrobial assay for clinical isolates, and TPC were measured by DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity, agar well diffusion method, and Folin–Ciocalteu assay respectively. Hydro-methanolic extract confirmed the presence of alkaloids, flavonoids, tannins, phenols, saponins, steroids, and glycosides as primary and secondary metabolites, which was later confirmed by TLC. FT-IR spectroscopy revealed the presence of alkanes, alkenes, alkyl halides, halogen compounds, primary alcohol, tertiary alcohol, aldehyde, aromatic amine, secondary amines, amide group, and carboxylic acid. The crude extract was composed of a significant quantity of total phenolic content with 705 ± 0.40 mg GAE/g. Synergistically, the IC50 value of the crude extract and ascorbic acid was found to be 27.055 μg/ml and 37.244 μg/ml, respectively, which suggests that root extract possesses strong antioxidant properties. The majority of the microbial strains exhibited varying degrees of sensitivity to the root extract with a notable inhibitory effect against Escherichia coli, Klebsiella pneumoniae, and Penicillium glaucum.

Conclusion

The findings of this analysis suggest that the hydro-methanolic extract from S. urens root exhibit antioxidant activity quantified by its ability to scavenge DPPH; antimicrobial activity displayed appreciable microbial sensitivity. These properties are associated with the presence of high phenolic content, different secondary metabolites, and their functional groups. The results are suggestive that S. urens root is rich in bioactive compounds, which serve as a novel natural source for potential therapeutic applications.

Graphical abstract

Antioxidant, Anti-Inflammatory, and Antidiabetic Activities of Leaves and Stems of Uapaca bojeri Bail. (EUPHORBIACEAE), an Endemic Plant of Madagascar

Uapaca bojeri is an endemic Malagasy plant used by the local population. This work aimed to evaluate antioxidant, anti-inflammatory, and antidiabetic activities of the methanol extracts of U. bojeri leaves and stems and to report their total phenolic content and the bioactive compound content by HPLC methods. Antioxidant capacity was determined by DPPH and ferric reducing antioxidant power (FRAP) assays. An in vivo carrageenan-induced paw oedema and acetic acid-induced writhing test in mice were used for anti-inflammatory activity evaluation. An oral glucose tolerance test was performed in mice to evaluate antidiabetic activity. The total bioactive compound content of leaves was higher than that of stems. Stem methanol extract inhibited the free radical DPPH more than the leaf methanol extract. Leaf methanol extract inhibited, in a dose-dependent manner, the carrageenan-induced paw oedema more than the stem extract, but their inhibition of the pain symptoms caused an acetic acid-induced decrease similar to the number of writhes in the dose-dependent case. The leaf and stem methanol extracts significantly reduced blood glucose levels after 30 min of glucose loading in mice compared to the control group blood glucose reduction. The presence of several bioactive compounds in U. bojeri contributed to the different biological activities, but isolation and identification of these bioactive molecules are necessary to confirm these pharmacological properties.

Comprehensive evaluation of physicochemical properties and antioxidant activity of B. subtilis-fermented polished adlay subjected to different drying methods

The physicochemical properties and antioxidant activity of B. subtilis-fermented polished adlay (BPA) subjected to different drying methods (hot-air drying, HAD; infrared-radiation drying, IRD; vacuum drying, VD; microwave-vacuum drying, MVD; and freeze-vacuum drying, FVD) were evaluated in this study. Results showed FVD was ideal for maintaining the natural appearance and higher contents of proximate compositions, free fatty acids, tetramethylpyrazine (6.91 mg/g DW), coixol (0.62 mg/g DW), coixenolide (4.21% DW), coixan (35.10% DW), and triterpenoids (17.41 mg/g DW). The higher contents of total phenolics and flavonoids, stronger antioxidant activity, and higher color differences were observed in HAD and IRD samples. MVD displayed the shorter drying time, higher γ-aminobutyric acid content, and higher retention ratios of tetramethylpyrazine (75.54%), coixol (87.10%), coixenolide (98.57%), and coixan (99.11%). Pearson's correlation coefficient exhibited that the positive correlation between the contents of phenolics and flavonoids and the antioxidant activities of all dried BPA samples was observed (R 2 > 0.881, p < .05). Principal component analysis showed that the top three categories of comprehensive quality were FVD-, MVD-, and VD-treated BPA samples. In conclusion, MVD should be a potential preservation method to obtain high-quality dried BPA for short drying time and high comprehensive quality.

Effects of processing techniques on drying characteristics, physicochemical properties and functional compounds of green and red chilli (Capsicum annum L.) powder

This study was aimed to investigate the effect of processing techniques on the characteristics of green and red chilli powder. Four samples, such as pretreated green chilli paste (PTGP), pretreated green chilli longitudinal slit (PTGL), pretreated whole red chilli (PTWR) and untreated green chilli paste (UTGP), were prepared and dried at 60 °C in a cabinet dryer. The pretreatment was blanching in acetic acid solution and soaking immediately in a combined solution of Na₂S₂O₅ and CaCl₂. Pretreated samples took a shorter drying time than the untreated sample in reducing moisture content from 86.31 to 8%. Pretreatment before drying resulted in retaining total chlorophyll (~ 86%), phenolic compounds (~ 32%), green color, and pungency of chilli. Analysis result indicated that more than 60% retention of β-carotene was found while retention of ascorbic acid was comparable. Conclusively, this research reveals a good nutritional profile in cabinet dried green chilli powder, which may open the scope for commercial production.

Phytochemical, antioxidant, anti-proliferative and antimicrobial properties of Catharanthus roseus root extract, saponin-enriched and aqueous fractions

Catharanthus roseus (L.) G. Don (C. roseus) is a well-known medicinal plant for its source of alkaloids solely found in the leaves. Other parts including the root are usually discarded after the alkaloid extraction. This study sought to investigate phytochemical profiles, antioxidant, antimicrobial and cytotoxic properties of the C. roseus root extract (RE) and its two sub-fractions including saponin-enriched (SE) and aqueous (AQ) fractions. The results showed that the RE was a rich source of saponins (1744.44 mg ESE/g) and phenolics (51.27 mg GAE/g), which comprised of gallic acid (25.74 mg/g), apigenin (1.45 mg/g) and kaempferol (1.58 mg/g). The SE fraction was enriched with 31% of saponins and 63% of phenolics higher than those of the RE; whereas the concentrations of saponins and phenolics of the AQ fraction were lower than those of the RE by 40% and 74%, respectively. The content of gallic acid in the SE fraction was 1.4-fold and 1.5-fold higher than those of the RE or AQ fraction, respectively. The SE fraction demonstrated potent antioxidant capacity, which was significantly higher than the RE or AQ fraction, and also exhibited strong anti-proliferative activity against 11 cancer cell lines including A2780 (ovarian), H460 (lung), A431 (skin), MIA PaCa-2 (pancreas), Du145 (prostate), HT29 (colon), MCF-7 (breast), BE2-C (neuroblastoma), SJ-G2, U87 and SMA (glioblastoma) with low GI₅₀ values (≤ 2.00 µg/mL). The SE fraction was also shown to effectively inhibit the growth of both bacteria (Escherichia coli, Enterobacter aerogenes and Staphylococccus lugdunensis) and fungi (Candida albicans and Aspergillus niger). These findings warrant further investigation to isolate major compounds from the SE fraction and further test their antioxidant, anticancer and antimicrobial activities.

Improving the Vanillin-Sulphuric Acid Method for Quantifying Total Saponins

The colorimetric assay used for saponin quantification in plant extracts is subject to interference by common solvents used to extract the saponins from plant materials. Therefore, the degree of interference of ten common solvents was investigated. It was found that the presence of acetone, methanol and n-butanol in the reaction solution caused an intense darkening of the reaction solution in the absence of saponins, which likely could lead to erroneous saponin content values. Using aescin to construct standard curves with different solvents—such as water, ethanol, and methanol— also showed significant differences in the standard curves obtained, which led to different values when they were applied to quantify the saponin content of an ethanol extract from dried and powdered Gac (Momordica cochinchinensis Spreng) seed kernels. To improve the method, a solvent evaporation step was added prior to the colorisation reaction to prevent undesired solvent interference during the reaction step. Using this modified protocol for the aescin standard curve and the Gac seed kernel extract eliminated any solvent interference. Thus, this improved protocol is recommended for the quantification of the saponin content of plant extracts irrespective of which extraction solvent is used.