Anti-inflammatory, wound healing and antioxidant potential of compounds from Dioscorea bulbifera L. bulbils

Abstract

Background Dioscorea bulbifera L. (Dioscoreaceae) has been traditionally used in Thai folk medicine as a diuretic and anthelmintic, for longevity preparations, and for wound and inflammation treatment. This plant is also commonly used in traditional Indian and Chinese medicines in the treatment of sore throat, gastric cancer, rectal carcinoma and goiters. However, the wound healing effects of the active compounds in this plant have not been investigated. Objective This study aimed to identify compounds responsible for the wound healing activity of D. bulbifera and determine their potential anti-inflammatory and antioxidant activities. Methods Crude extracts of D. bulbifera bulbils, their derived fractions and eleven purified compounds were tested for anti-inflammatory activity against LPS-induced NO production in RAW264.7 macrophages. The wound healing effects were evaluated via cell proliferation and migration assays using human dermal fibroblasts (HDFs), and the antioxidant effects were determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical (•OH) scavenging activity assays. Results 15,16-Epoxy-6α-O-acetyl-8β-hydroxy-19-nor-clero-13(16),14-diene-17,12;18,2-diolide (2), (+)-catechin (5), quercetin (6) and myricetin (11) exhibited significantly potent wound healing effects and promoted marked cell proliferation, resulting in % viabilities of 107.4–137.6, 121.1–151.9, 98.0–131.9, 90.9–115.9, respectively. Among them, (+)-catechin produced the highest % cell migration, resulting in 100.0% wound closure sooner (at day 2) than the other compounds. In addition, 1 μg/ml (+)-catechin significantly increased fibroblast migration by 2.4-fold compared to that in the control after 24 h. Regarding anti-inflammatory properties, kaempferol (7) and quercetin (6) decreased (p < 0.005) NO production, with IC50 values of 46.6 and 56.2 μM, respectively. In addition, the crude extracts, solvent fractions and flavonoid compounds were also found to possess marked antioxidant activity in both DPPH and •OH radical scavenging assays. Conclusions These findings provide more evidence to support the traditional use of D. bulbifera for the treatment of wounds and inflammation.

Formulation and Optimal Design of Dioscorea bulbifera and Honey-Loaded Gantrez®/Xyloglucan Hydrogel as Wound Healing Patches

“…The antioxidant activity of the D. bulbifera extract/honey-loaded Gan/XG after being incubated for 1 h significantly increased when the incubation time increased. The result of the D. bulbifera extract/honey-loaded Gan/XG correlated with a previous study showing that the ethanolic extract of D. bulbifera bulbils exhibited antioxidant activity by the DPPH radical scavenging assay [25]. The antioxidant patches are the alternative for treatment of difficult-to-heal wounds because the antioxidants help to manage wound oxidative stress and balance the level of reactive oxygen species [37][38][39].…”

“…Moreover, the viability of cells treated with the extraction media of the D. bulbifera extract/honey-loaded Gan/XG and the unloaded Gan/XG at the concentration of 1 mg/mL was significantly higher than the control (Figure 7). The results of the D. bulbifera extract/honey-loaded patch related to the previous study of D. bulbifera ethanolic extract with concentrations from 1 to 100 µg/mL that exhibited low toxicity [25].…”

“…The tuber extract showed an improvement in wound contraction and a reduction of the epithelialization period compared with standard ointment [24]. Chaniad et al found that four compounds from D. bulbifera bulbils significantly improved wound healing [25]. The authors also investigated viability, proliferation, and migration of fibroblasts treated with D. bulbifera extract gel for treating wounds.…”

Effects of Quercetin and Curcumin Combination on Antibacterial, Antioxidant, In Vitro Wound Healing and Migration of Human Dermal Fibroblast Cells

“…Among the natural polyhydroxy flavonoids, quercetin has strong antioxidant and anti-inflammatory properties to regulate oxidative stress and inflammation, which delay the wound healing process [ 9 ]. It has been shown that quercetin can promote the wound healing process by modulating inflammatory cells and increasing fibroblast proliferation while decreasing immune cell infiltration, fibrosis and scar formation, and creating changes in signaling in fibrosis-associated signaling pathways [ 10 , 11 , 12 ]. A previous report revealed that quercetin accelerated diabetic wound repair by inhibiting inflammatory reactions via modulating macrophage polarization [ 13 ].…”

Wound Healing Properties and Antimicrobial Effects of Parkia clappertoniana Keay Fruit Husk Extract in a Rat Excisional Wound Model

“…Further, colorimetric phytochemical test was used to confirm the presence of catechin and quercetin in PCFHE, indicating that the wound healing and antimicrobial effects of PCFHE are attributable to its phyto-components particularly catechin and quercetin. This assertion is in view of the confirmed wound healing, antioxidant, anti-inflammatory, and antimicrobial effects of catechin and quercetin [ 44 , 45 ]. For instance, quercetin and catechins demonstrate free radical scavenging, anti-inflammatory, antioxidant, antihistamine effect, inhibition of matrix metalloproteinase, and promote collagen synthesis [ 46 – 48 ], and all these properties are crucially involved in wound healing process [ 49 ].…”