Depression is the most common form of mental illness and the major cause of disability worldwide. Symptoms of depression, including feelings of intense sadness and hopelessness, may occur after a specific event or in response to a gradual decline in health and functional status, often associated with aging. Current therapies for treating these symptoms include antidepressant drugs, counseling and behavioral therapy. However, antidepressant drugs are associated with mild to severe adverse effects, which has prompted the need for better treatment options. Medicinal mushrooms are valuable sources of food and medicine and are increasingly being used as supplements or as alternative medicines in standard healthcare. Numerous studies have provided insights into the neuroprotective effects of medicinal mushrooms, which are attributed to their antioxidant, anti-neuroinflammatory, cholinesterase inhibitory and neuroprotective properties. In this review, we comprehensively examine the role of these medicinal mushrooms in the treatment of depression. However, to apply these natural products in clinical settings, the therapeutic agent needs to be properly evaluated, including the active ingredients, the presence of synergistic effects, efficient extraction methods, and stabilization of the active ingredients for delivery into the body as well as crossing the blood-brain barrier.
Five culinary-medicinal mushrooms are commonly available in the Malaysian market: Agaricus bisporus (white and brown), Ganoderma lucidum, Hypsizygus marmoreus, Pleurotus floridanus, and P. pulmonarius. These species were selected for use in the current study, the aim of which was to investigate the antimelanogenesis and anti-inflammatory activity of these mushrooms in an attempt to evaluate their potential use in cosmeceuticals. Mushroom fruiting bodies were extracted with hot water, and the extracts were freeze-dried before testing. The antimelanogenesis activity of the extracts was determined by cell viability assay, measurement of intracellular melanin content, and cellular tyrosinase assay with B16F10 melanoma cells. The anti-inflammatory activity of the mushroom extracts was tested by measuring the levels of nitric oxide (NO), tumor necrosis factor (TNF)-α, and interleukin-10 excreted by RAW264.7 macrophages. Brown A. bisporus reduced intracellular melanin content to the largest extent-up to 57.05 ± 3.90%-without a cytotoxic effect on B16F10 melanoma cells. This extract also reduced cellular tyrosinase activity to 17.93 ± 2.65%, performing better than kojic acid, the positive control. In parallel, the extract from brown A. bisporus, at the highest concentration tested, has appreciable anti-inflammatory activity through reductions of NO and TNF-α levels. The other 5 extracts showed moderate antimelanogenesis and anti-inflammatory activities. In summary, our findings show that A. bisporus (brown) extract has the potential to be used as an ingredient in whitening skincare products and to sooth the inflammatory response on the skin.