Antioxidant phenolic compounds from Smilax sebeana Miq

Chemical composition, antifungal, and anti-virulence action of the stem bark of Hancornia speciosa Gomes (Apocynaceae) against Candida spp

ETHNOPHARMACOLOGICAL RELEVANCE

Hancornia speciosa Gomes is a fruit and medicinal species used for treating infectious diseases of the genitourinary system. However, its mechanism of action against microbes is still not fully understood. Infections in the genitourinary system caused by Candida spp. are associated with its fungal resistance and pathogenicity. New plant-derived compounds are an alternative to fight these Candida infections.

AIM OF THE STUDY

The objective of this study was to evaluate the anti-Candida effects of extracts of the stem bark of H. speciosa. This research investigated the chemical composition of sulfuric ether (EEHS) and methanolic (MEHS) extracts, their drug-modifying action on fluconazole, and their anti-virulence action on the morphological transition of Candida species.

MATERIALS AND METHODS

The extracts (EEHS and MEHS) of the stem bark of H. speciosa were chemically characterized via qualitative phytochemical screening and by liquid chromatography coupled with mass spectrometry (UPLC-MS-ESI-QTOF). The extracts were evaluated regarding their antifungal effects and fluconazole-modifying activity against Candida albicans, Candida krusei, and Candida tropicalis using the broth microdilution method. Additionally, the study evaluated the inhibition of fungal virulence in Candida species through morphological transition assays.

RESULTS

The phytochemical screening revealed the presence of anthocyanidins, anthocyanins, aurones, catechins, chalcones, flavones, flavonols, flavanones, leucoanthocyanidins, tannins (condensed and pyrogallic), and xanthones in both extracts of the stem bark of H. speciosa. The UPLC-MS-ESI-QTOF analysis identified the same compounds in both extracts, predominating phenolic compounds. Some compounds were first time recorded in this species: gluconic acid, cinchonain IIb, cinchonain Ib isomer, and lariciresinol hexoside isomers. Most of the intrinsic antifungal activity was observed for the MEHS against C. krusei (IC50: 58.41 μg/mL). At subinhibitory concentrations (MC/8), the EEHS enhanced the action of fluconazole against all Candida strains. The MEHS exhibited greater efficacy than fluconazole inhibiting C. krusei growth. The EEHS completely inhibited hyphae appearance and reduced pseudohyphae formation in C. albicans.

CONCLUSION

The stem bark of H. speciosa is a rich source of bioactive compounds, especially phenolic. Phenolic compounds can have important roles in fighting infectious diseases of the genitourinary system, such as candidiasis. The extracts of H. speciosa improved the action of the drug fluconazole against Candida species, inhibited hyphae appearance, and reduced pseudohyphae formation. The results of this study can support the development of new therapeutics against resistant strains of Candida.

Optimization and evaluation of Atrina pectinata polysaccharides recovered by subcritical water extraction: A promising path to natural products

In this study, the recovery of Atrina pectinata posterior adductor polysaccharides (APP-PS) using subcritical water extraction (SWE) was optimized by response surface methodology (RSM) and the physicochemical and biological properties of the recovered APP-PS were evaluated. The optimal extraction conditions, which resulted in a maximum yield of 55.58 ± 1.12 %, were temperature, 152.08 °C; extraction time, 10 min; solid-liquid ratio, 30 g/600 mL. The obtained APP-PS was found to be 88.05 ± 0.17 % total sugar. Fourier transform infrared (FT-IR) and Nuclear magnetic resonance (NMR) analyses confirmed the presence of the α-coordination of D-glucan in the polymer sample. The analysis of monosaccharide composition, along with thermogravimetric analysis, revealed the typical structure of the sample, composed of glucose alone. Total phenolic contents of APP-PS were measured as 5.47 ± 0.01 mg Gallic acid/g of dry sample and total flavonoids contents were determined to be 0.78 ± 0.06 mg Quercetin/g of dry sample. For biological activities, ABTS+, DPPH and FRAP antioxidant activities were measured to be 20.00 ± 0.71, 2.35 ± 0.05 and 4.02 ± 0.07 μg Trolox equivalent/100 g of dry sample, respectively. Additionally ACE inhibitory was confirmed to be 87.02 ± 0.47 %. These results showed that SWE is an effective method to recover biofunctional materials from marine organisms.

Smilax aristolochiifolia Root Extract and Its Compounds Chlorogenic Acid and Astilbin Inhibit the Activity of α-Amylase and α-Glucosidase Enzymes

Regulating activities of α-amylase and α-glucosidase through the use of specific inhibitors is a main strategy for controlling type 2 diabetes. Smilax aristolochiifolia root decoctions are traditionally used in Mexico as hypoglycemic and for weight loss, but the active principles and mechanisms underlying such putative metabolic effects are yet unknown. Here, we isolated the major bioactive compounds from a hydroethanolic extract of S. aristolochiifolia root by fast centrifugal partition chromatography and evaluated their effects against pancreatic α-amylase and yeast α-glucosidase. A chlorogenic acid-rich fraction (CAF) inhibited α-amylase activity with an IC₅₀ value of 59.28 μg/mL in an uncompetitive manner and α-glucosidase activity with an IC₅₀ value of 9.27 μg/mL in a noncompetitive mode. Also, an astilbin-rich fraction (ABF) inhibited α-glucosidase activity with an IC₅₀ value of 12.30 μg/mL, in a noncompetitive manner. CAF inhibition α-amylase was as active as acarbose while both CAF and ABF were 50-fold more potent inhibitors of α-glucosidase than acarbose. The molecular docking results of chlorogenic acid and astilbin with α-amylase and α-glucosidase enzymes correlated with the inhibition mechanisms suggested by enzymatic assays. Our results prove that S. aristolochiifolia roots contain chlorogenic acid and astilbin, which inhibit carbohydrates-hydrolyzing enzymes, suggesting a new mechanism for the hypoglycemic effect reported for this plant.

Phytochemical and Antinociceptive, Anti-Inflammatory, and Antioxidant Studies of Smilax larvata (Smilacaceae)

The tea of aerial parts of Smilax larvata Griseb. (Smilacaceae) has been ethnopharmacologically used in Southern Brazil due to its anti-inflammatory action. In this study, ethanolic and organic extracts from aerial parts of S. larvata were phytochemically and pharmacologically characterized. The phytochemical analysis of EtOAc extract of S. larvata revealed the presence of three flavonoids, drabanemoroside, kaempferol 3-O-α-L-rhamnopyranosyl(1→2)-α-L-rhamnopyranoside, and kaempferol, the first two being isolated for the first time in this genus, two phenolic compounds p-hydroxybenzoic acid and p-coumaric acid, and alkaloids. In vitro assays demonstrated a potential antioxidant property of SLG. The treatment with SLG induced a significant reduction of the formalin-evoked flinches in rats, an effect reversed by opioid antagonist naloxone. Treatment with SLG also induced a significant increase in the hot plate latency and a decrease of intestinal motility by 45%. No effect was observed over nociceptive responses induced by a TRPA1 agonist mustard oil or over acetic acid-induced writhing in mice. Together, our data suggested that SLG has an in vivo antinociceptive effect, which seems to be associated with the opioid system activation. These findings support previous claims of medical use of Smilax larvata in the treatment of pain conditions.

Antioxidant and Antiglycating Constituents from Leaves of Ziziphus oxyphylla and Cedrela serrata

Ziziphus oxyphylla and Cedrela Serrata plants have a folkloric use in Pakistan for treatments of different ailments, i.e., Jaundice, Hepatitis, Diabetes, and antimicrobial. Until now, none of the research studies have reported any phytochemical work on leaves of these two plants. This study aimed to isolate and perform phytochemical analysis in order to search for the constituent having the active role in treatment of the aforementioned ailments. A bioassay-guided fractionation and isolation procedure was used to isolate the concerned phytochemicals present in leaf extracts of Z. oxyphylla and C. serrata. The process involved the hyphenated techniques, i.e., Flash Chromatography, Semi-Preparative HPLC/DAD, UPLC/MS, and NMR in order to isolate and elucidate the structure of the phytochemicals. Seven compounds (1–7) were isolated and identified as flavonoids, more in particular glycosides of quercetin and kaempferol. They showed DPPH scavenging activity, compound 3 (isoquercitrin) being the most active one with an IC50 of 10.8 µg/mL (positive control quercetin; IC50 3.6 µg/mL). The superoxide-radical scavenging and total antioxidant (ABTS) assays indicated IC50 values ranging from 200 to 910 µg/mL and 170 to 320 µg/mL, respectively (positive control quercetin: 374 and 180 µg/mL, respectively). Furthermore, these compounds had low IC50 values for inhibition of protein glycation (AGEs inhibition), ranging from 530 to 818 µg/mL, comparable to aminoguanidine (510 µg/mL) used as a positive control. This study resulted in the identification of seven flavonoid glycosides for the first time from the leaves of Z. oxyphylla and C. serrata with antioxidative and antiglycating activities.