Enhancement of Vitamin D2 Levels in Pleurotus ostreatus Using Ultraviolet Irradiation and Assessing Its Effect on Dexamethasone-Induced Osteoporosis in Mice

Mushrooms are a dietary source of vitamin D2 because they contain ergosterol, which can be converted into vitamin D2 after exposure to ultraviolet (UV) irradiation. UVB irradiated mushrooms contain high active vitamin D. A regular consumption of UVB‐irradiated mushrooms has been shown to be effective to increase bone calcification and modulation of host immunity. This study aimed to enhance vitamin D2 formation in oyster mushrooms (Pleurotus ostreatus) using UVB irradiation and to assess its effect on dexamethasone induced osteoporosis in mice.) Oyster mushrooms were UVB-irradiated with a UVB lamp at the dose of 8.01 J/cm2 - 24.03 J/cm2. The vitamin D2 level was measured using high performance liquid chromatography (HPLC) with calciferol as the standard. The powder of vitamin D enriched oyster mushroom powder was then referred to as Oyster-D. Dexamethasone (0.01 ml/g) induced osteoporosis in BALB/c mice. The number of osteoclasts, osteoblasts, osteocytes of the femur was assessed using hematoxylin-eosin staining. Serum calcium level was measured with spectrophotometry. UVB irradiation with the dose of 48.06 J/cm2 resulted in a highest vitamin D2 concentration, up to 11.333 µg/g. There was a significant increase in the number of osteoclasts, osteoblasts and serum calcium levels and decrease in the number of osteoclasts. The results suggest that UVB irradiation increased vitamin D2 levels in white oyster mushrooms and vitamin D enriched oyster mushrooms have a potential as anti-osteoporosis.