Abstract:
Anthocyanins are an important group of highly hydro-soluble pigments in most species of plants that are
produced by secondary metabolism of plants through the pentose phosphate, shikimate and flavonoid
pathways and are accumulated in cell vacuoles. They are polyphenols with strong antioxidant activity,
which is largely responsible for some biological activities including prevention or lowering the risk of
cardiovascular diseases, diabetes, arthritis and cancer. In fruits and vegetables anthocyanins are present in
the form of glycosides. Anthocyanins have also been enhanced in tea through conventional breeding with
the first generation purple tea cultivars already released for commercial utilization. Further purple tea
improvement programme in Kenya has led to development of second generation purple tea plants focusing
on further enhancement of anthocyanins content. A study involving second generation tea cultivars
established in four experimental fields in Kenya namely; Timbilil, Kangaita, Nandi and Chesumot,
compared levels of production of anthocyanins in the tea cultivars with purple-pigmented fruits and
vegetables purchased from Kericho market. Total anthocyanin content was quantified by pH differential
method using a UV- spectrophotometer, while radical scavenging activity of the tea extracts was assessed
using 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH). There were significant (p≤0.05) differences, in the
anthocyanins content among the tea varieties, fruits and vegetables. The anthocyanin contents in the tea
cultivars ranged from 38.6 to 1037.0 mg/l, 169.7 to 501.0 mg/l, 78.3 to 682.1 mg/l and 19.7 to 876.9 mg/l,
in Timbilil, Kangaita, Nandi and Chesumot, respectively. In the pigmented fruits and vegetables, the
anthocyanin content was 1.5 and 425.3 mg/l for beetroot and red cabbage, respectively. The radical
scavenging activity of second generation purple tea ranged from 82.8 to 91.5 % compared the pigmented
fruits and vegetables that exhibited lower radical scavenging capacity of 1.14 to 45.3%. The observed
enhanced level in the anthocyanins content and radical scavenging activity within some of the second
generation purple teas have demonstrated the availability of improved cultivars with greater potential in
antioxidant capacity and suitable alternative as super food for health conscious populations.
