Anti-inflammatory and wound healing potential of cashew apple juice (Anacardium occidentale L.) in mice

Abstract

Cashew apple is a tropical pseudofruit consumed as juice due to its excellent nutritional and sensory properties. In spite of being well known for its important antioxidant properties, the cashew apple has not been thoroughly investigated for its therapeutic potential. Thereby, this study evaluated the antioxidant capacity, anti-inflammatory, and wound-healing activities of cashew apple juice. Juices from ripe and immature cashew apples were analyzed for antioxidant, anti-inflammatory, and wound-healing properties. Those were evaluated in murine models of xylene-induced ear edema and wound excision. Swiss mice were treated with cashew juice by gavage. Edema thickness was measured and skin lesions were analyzed by planimetry and histology. Both antioxidant content and total antioxidant activity were higher in ripe cashew apple juice (RCAJ) than in unripe cashew apple juice (UNCAJ). The UNCAJ presented the main anti-inflammatory activity by a significant inhibition of ear edema (66.5%) when compared to RCAJ (10%). Moreover, UNCAJ also showed the best result for wound contraction (86.31%) compared to RCAJ (67.54%). Despite of higher antioxidant capacity, RCAJ did not promote better anti-inflammatory, and healing responses, which may be explained by the fact that treatment increased antioxidants level leading to a redox "imbalance" turning down the inflammatory response modulation exerted by reactive oxygen species (ROS). The results suggest that UNCAJ presents a greater therapeutic activity due to a synergistic effect of its phytochemical components, which improve the immunological mechanisms as well as an optimal balance between ROS and antioxidants leading to a better wound healing process.

Keywords: Anacardium occidentale; antioxidants; inflammation; wound healing activity.

Figure 1

Effect of cashew apple juice on wound healing. Macroscopic analysis of the progress of wound healing (a) and development of the unhealed wound area (mm²) over time (b). Groups: Water, Reference (REF), Ripe Cashew Apple Juice (RCAJ), and Unripe Cashew Apple Juice (UNCAJ) in 0, 3, 7, 14, and 21 days. * p < 0.05 compared to water group

Figure 2

Microscopic view of hematoxylin and eosin stained sections of wound tissues on day 14. (I) Water, (II) Reference (REF), (III) Ripe Cashew Apple Juice (RCAJ), and (IV) Unripe Cashew Apple Juice (UNCAJ). (a) Re-epithelized epidermis with keratin, (b) new capillary vessels, (c) mononuclear cells, (d) fibroblast proliferation, (e) reorganization fibers collagens. Original magnification: 100 ×(Scale bar: 200 µm)