Oxalis triangularis

Abstract: Ten fatty acid alkyl esters isolated from Oxalis triangularis, were evaluated for the effects on melanogenesis using mouse B16 melanoma cells. Treatment of methyl linoleate, methyl linolenate, ethyl linoleate and ethyl linolenate significantly blocked forskolin-induced melanogenesis and inhibited tyrosinase activity. In addition, we found that they inhibited cAMP production, suggesting that their anti-melanogenic effect is mediated by the inhibition of cAMP production. We concluded that methyl/ethyl linoleate and linolenate isolated from Oxalis triangularis have pigment inhibition activity. These compounds may be useful as the cosmetic agent to stimulate skin whitening.

Abstract: The purpose of this study was to clarify effects of anthocyanins on photosynthesis and photoinhibition in green and red leaves of Oxalis triangularis. Gas analysis indicated that green plants had the highest apparent quantum yield for CO2 assimilation [0.051 vs. 0.031 μmol(CO2) μmol−1(photon)] and the highest maximum photosynthesis [10.07 vs. 7.24 μmol(CO2) m−2 s−1], while fluorescence measurements indicated that red plants had the highest PSII quantum yield [0.200 vs. 0.143 μmol(e−) μmol−1(photon)] and ETRmax [66.27 vs. 44.34 μmol(e−) m−2 s−1]. Red plants had high contents of anthocyanins [20.11 mg g−1(DM)], while green plants had low and undetectable levels of anthocyanin. Red plants also had statistically significantly (0.05>p>0.01) lower contents of xanthophyll cycle components [0.63 vs. 0.76 mg g−1(DM)] and higher activities of the reactive oxygen scavenging enzyme ascorbate peroxidase [41.2 vs. 10.0 nkat g−1(DM)]. Anthocyanins act as a sunscreen, protecting the chloroplasts from high light intensities. This shading effect causes a lower photosynthetic CO2 assimilation in red plants compared to green plants, but a higher quantum efficiency of photosystem II (PSII). Anthocyanins contribute to photoprotection, compensating for lower xanthophyll content in red plants, and red plants are less photoinhibited than green plants, as illustrated by the Fv/Fm ratio.

Abstract: Oxalis triangularis is an attractive ornamental plant propagated by using bulbs and has no natural viable seeds. It is an ideal decorative plant for growing in pots and other containers. The plant is not widely found in Malaysia and mostly obtained from Thailand. Hence, it is necessary to propagate this plant through tissue culture system for large scale production. In the present study, production of synthetic seeds was attempted from this species and the synthetic seeds managed to survive after 7 and 30 days after storage at 4°C. The rate of synthetic seeds conversion to complete plants after 7 days was 96.67% with 4.57 mean shoot numbers, while after 30 days of storage, the conversion rate slightly decreased to 90% with only 3.97 shoots formation per bead. The present work reports and discusses the potential of tissue culture technique as an alternative method for mass propagation and conservation of this interesting and attractive ornamental plant for future uses and exploitation.