Ogimi, the SHIKUWASA village

SHIKUWASA originates from Mt. Nekumachiji (360m), the symbol of Ogimi, and the ranging limestone mountainside. Sweet and sour, the unique, addictive flavor supports beauty, health and longevity. Its golden deliciousness is a gift from the limestone forest. (左写真:村の木/シークヮーサー)

A small, rutaceous citrus fruit native to Okinawa with loose skin, that is strongly sour when green and unripe, and balanced between sweet and sour when yellow and ripened.
Origin of the name
"Shii" means sour, and "Kwahsah" means to feed.
Main nutrients and effects
Improves metabolism and contains large amounts of vitamin C, good for recovery from exhaustion and beauty, as well as vitamin B1, carotene and various minerals. One of its nutrients, nobiletin, has received special attention for its longevity benefits after it was found that it had a cancer inhibiting effect.
About kuganii
SHIKUWASA has many known varieties, such as ishikunibu, fusubuta, tanebuto, mikangwa, ingwakunibu, hijahkunibu, ka-achii, kahbishii and 5 -6 more. The one that improved on these is kuganii. Kuganii means "golden" in the Okinawan dialect, a reference to the color of the fruit when ripened. It is most delicious from December to the end of January.

The diverse features of SHIKUWASA

【SHIKUWASA special lecture】

Tokyo University of Pharmacy and Life Science School of Pharmacy Professor
From the talks of Dr. Yutaka Sashida
At the Ogimi Rural Environment Improvement Center, on Dec. 12th, 1998



Domestically produced citrus fruits have seen a reduction in demand stemming from the deregulation of imports and lifestyle changes. Citrus fruits, however, contain copious amounts of physiologically active nutrients, such as flavonoids, carotenoids, synephrine and vitamin C, and by using these to improve dietary habits, are believed to have a preventative effect on lifestyle-related diseases. With this in mind and because of the high expectations for mandarin oranges as a health-promoting food, we decided to examine the functional nutrients contained in SHIKUWASA.

Experimental results

  • In the skin and juice, SHIKUWASA was found to contain large amounts of 6 flavonoids, such as tangeretin and nobiletin.
  • 1 mg / 20 μl each of tangeretin and nobiletin were applied to the ears of mice, followed by the cancer promoter TPA, and the cancer inhibition ratio was observed 6 weeks later. The results were that the ears that had tangeretin and nobiletin applied showed a 65% and 75% inhibition ratio, respectively.
  • Additionally, strongly active methylnobiletin and nobiletin were found in cells infected with a cancer-inducing virus when cancer antibodies were investigated.
  • Based on these two results, a strong cancer prevention effect was expected of nobiletin. When the the skin cancer inhibiting effect in mice was investigated after 20 weeks, a clear reduction in carcinogenesis could be seen.
  • Using synovial cells and cartilage cells from rabbits, when the effect on enzymes related to chronic rheumatoid arthritis were investigated, nobiletin was found to inhibit the increase of these enzymes.
  • When nobiletin was administered to mice orally, a pain relieving effect and granulation proliferation inhibiting effect were noticed.
  • Even when compared to other citrus fruits, SHIKUWASA is high in tangeretin and nobiletin. (Table 1). These are also contained in SHIKUWASA processed foods (Table 2). However, the amount contained in individual SHIKUWASA can vary significantly.
Table 1) ■ All commercially available citrus fruit drinks (100%) tangeretin and nobiletin content ( /ml )
Name Tangeretin Nobiletin
SHIKUWASA 7.0 12.3
Grapefruit 0.0 0.0
Orange 0.4 1.7
Satsuma Mandarin 0.2 0.2
SHIKUWASA Juice (raw) 0.3 0.4
(Table 2) ■ SHIKUWASA products tangeretin and nobiletin content ( /g wet )
Product Tangeretin Nobiletin
Pastry 8.4 13.3
Rice cake 23.1 34.2
Sponge Cake 10.1 15.0
Jelly 12.5 34.7
Jam 18.8 44.5
Candy A n.d. n.d.
Candy B 7.8 19.0
Noodles 5.2 4.1