Health Ingredient to support the prevention of osteoporosis*
Unshiu mikan or Citrus Unshiu Marc is commonly known as Satsuma, Satsuma Mandarin or Satsuma Orange in the Western society. Unshiu mikan is originated from Kagoshima (Satsuma).
There are approximately 900 species of citrus in the world. Japanese oranges are unique to Japan and appeared 1,200 years ago. It was regarded as fruit for perpetual youth and longevity as described in Kojiki and Nihon Shoki. Citrus unshiu is rich in carotenoids, (β-cryptoxanthin, β-carotene), coumarins (auraptene, etc), limonoids (limonins, etc), and flavonoids (tangeretin, nobiletin, hesperidin).
Osteoporosis, or porous bone, is a disease characterized by low bone mass and structural deterioration of bone tissue, leading to bone fragility and an increased susceptibility to fractures of the hip, spine and wrist. Osteoporosis is a multifactorial disease and is influenced by factors like nutrition, hormone and physical activity. The process of bone resorption and reformation is continuous, and osteoclasts are important in the regulation of bone metabolism. Osteoblasts decrease with age while growth, maintenance and constant repair of bone tissue depend on the balance between rates of bone resorption and bone formation. Osteoporosis occurs when rate of bone resorption is greater than bone formation leading to loss of bone mass.*
Osteoclasts are multinucleated cells associated with bone resorption process. Osteoclasts usually present in large quantities in porous bone surface. Bone density and bone mass is maintained through a balance of continuous process of bone resoprtion by osteoclasts and bone formation by osteoblasts. Recent studies suggested that estrogen receptor α is present in osteoclasts and effectively inhibits bone resorption. Production of estrogen decreases in menopause causing an imbalance in bone metabolism. Osteoporosis arises as rate of bone resorption increases.*
Theoretically, inhibiting production of osteoclasts may prevent activity of bone resorption, hence prevention against osteoporosis. A study was conducted to examine the effect of Citrus Unshiu Extract on osteoclasts. Osteoclast cells culture kit (by Hokudo Co.) was used. Study shown that β-cryptoxanthin of Citrus Unshiu Extract inhibited the production of osteoclasts at concentration 0.05μg/ml and 0.5μg/ml. Citrus Unshiu Extract is beneficial in the prevention of osteoporosis with its inhibitory effect on osteoclasts production.*
Additional test were done on mice regarding the effects of Citrus Unshui extract on bone density and bone strength. Bone mineral density was measured using pQCT method. The metaphysis and disphysis of mice femoral bone were measured. The bone mineral density was significantly higher and bone strength improved when fed Citrus Unshui.*
