The objectives of this study were to identify the antioxidants and antioxidant axtivity in 27 of Taiwan’s indigenous vegetables. Lycium chinense (Lc), Lactuca indica (Li), and Perilla ocymoides (Po) contained abundant quercetin (Que), while Artemisia lactiflora (Al) and Gynura bicolor (Gb) were rich in morin and kaempferol, respectively. Additionally, Nymphoides cristata (Nc) and Sechium edule (Se)-yellow had significantly higher levels of myricetin (Myr) than other tested samples. Cyanidin (Cyan) and malvidin (Mal) were abundant in Gb, Abelmoschus esculentus Moench (Abe), Po, Anisogonium esculentum (Retz.) Presl (Ane), Ipomoea batatas (Ib)-purple, and Hemerocallis fulva (Hf)-bright orange. Relatively high levels of Trolox equivalent antioxidant capacity (TEAC), oxygen radical absorption capacity (ORAC), and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenger were generated from extracts of Toona sinensis (Ts) and Po. Significant and positive correlations between antioxidant activity and polyphenols, anthocyanidins, Que, Myr, and morin were observed, indicating that these phytochemicals were some of the main components responsible for the antioxidant activity of tested plants. The much higher antioxidant activity of Po, Ts, and Ib (purple leaf) may be related to their higher Cyan, Que, and polyphenol content.

Background: Herbaceous plants containing antioxidants can protect against DNA damage. Thepurpose of this study was to evaluate the antioxidant substances,antioxidant activity, and protection of DNA from oxidative damage in humanlymphocytes induced by hydrogen peroxide (H₂O₂). Ourmethods used acidic methanol and water extractions from six herbaceousplants, including Bidens alba (BA), Lycium chinense (LC),Mentha arvensis (MA), Plantago asiatica (PA),Houttuynia cordata (HC), and Centella asiatica(CA). Methods: Antioxidant compounds such as flavonol and polyphenol were analyzed.Antioxidant activity was determined by the inhibition percentage ofconjugated diene formation in a linoleic acid emulsion system and bytrolox-equivalent antioxidant capacity (TEAC) assay. Their antioxidativecapacities for protecting human lymphocyte DNA fromH₂O₂-induced strand breaks was evaluated by cometassay. Results: The studied plants were found to be rich in flavonols, especially myricetinin BA, morin in MA, quercetin in HC, and kaemperol in CA. In addition,polyphenol abounded in BA and CA. The best conjugated diene formationinhibition percentage was found in the acidic methanolic extract of PA.Regarding TEAC, the best antioxidant activity was generated from the acidicmethanolic extract of HC. Water and acidic methanolic extracts of MA and HCboth had better inhibition percentages of tail DNA% and tail moment ascompared to the rest of the tested extracts, and significantly suppressedoxidative damage to lymphocyte DNA. Conclusion: Quercetin and morin are important for preventing peroxidation and oxidativedamage to DNA, and the leaves of MA and HC extracts may have excellentpotential as functional ingredients representing potential sources ofnatural antioxidants.

Mangrove ecosystems are vulnerable to rising sea levels as the plants are exposed to high salinity and tidal submergence. The ways in which these plants respond to varying salinities, immersion depths, and levels of light irradiation are poorly studied. To understand photosynthesis in response to salinity and submergence in mangroves acclimated to different tidal elevations, two-year-old seedlings of two native mangrove species, Kandelia obovata and Rhizophora stylosa, were treated at different salinity concentrations (0, 10, and 30 part per thousand, ppt) with and without immersion conditions under fifteen photosynthetic photon flux densities (PPFD μmol photon·m⁻²·s⁻¹). The photosynthetic capacity and the chlorophyll fluorescence (ChlF) parameters of both species were measured. We found that under different PPFDs, electron transport rate (ETR) induction was much faster than photosynthetic rate (Pn) induction, and Pn was restricted by stomatal conductance (Gs). The Pn of the immersed K. obovata plants increased, indicating that this species is immersed-tolerant, whereas the Pn level of the R. stylosa plants is salt-tolerant with no immersion. All of the plants treated with 30 ppt salinity exhibited lower Pn but higher non-photochemical quenching (NPQ) and heat quenching (D) values, followed by increases in the excess energy and photoprotective effects. Since NPQ or D can be easily measured in the field, these values provide a useful ecological monitoring index that may provide a reference for mangrove restoration, habitat creation, and ecological monitoring.

Background: Spectral reflectance was evaluated for its usefulness as a nondestructive estimation of chlorophyll (Chl) content from three cultivars of sweet potato (Ipomoea batatas L.) with green, yellow, and purple leaves grown in a greenhouse for 22 days. While the green and yellow leaves contain variant amount of photosynthetic pigments without or with little level of anthocyanins, the purple leaves, except large amount of photosynthetic pigments, have high quantity of anthocyanins. Results: For green and yellow leaves, the reciprocal reflectance (R^-1) and derived indices incorporating near infrared (NIR) reflectance, [(R_λ)^-1 - (R_NIR)^-1] and [(R_NIR/R_λ) - 1], in the green and red edge spectral ranges were shown to be strongly correlated (r ² = 0.8 ~ 0.9) with the chlorophyll content. The root mean square error (RMSE) of the chlorophyll content estimation using these indices was < 50 mg m^-2. However, when purple leaves containing high levels of anthocyanins were included in the sample, R^-1 in the green spectral range and the above-mentioned indices displayed much weaker correlations with the chlorophyll content. The RMSE of chlorophyll estimation using these indices in the green spectral range sharply increased to > 110 mg m^-2 when the sample included purple leaves. The new index, [1 - (R_λ/R_NIR)], was therefore inferred and developed to eliminate the distorting effect of anthocyanins on chlorophyll content estimation using reflectance in the green spectral range. For leaves with high levels of anthocyanins, the correlation between [1 - (R_λ/R_NIR)] and the chlorophyll content remained strong (r² = 0.8 ~ 0.9) in the green spectral range, and the RMSE was minimal. Conclusion: The reflectance index, [1 - (R_λ/R_NIR)], therefore represents a new and useful parameter for estimating leaf chlorophyll content in leaves with any level of anthocyanins such as purple rice leaf.