Abstract
The present study aimed to examine the phytotoxic potential of seven Vietnamese tea samples based on the specific and total activity of caffeine and tea extracts on test plants. The sandwich method results indicated that the inhibitory effect of tea samples on the radicle and hypocotyl growth of lettuce seedlings was dependent on the concentration and type of tea samples, and also the presence of agar soluble allelochemicals. Among the seven tea samples, the leachates from Vinatea-green tea showed the highest inhibition on the radicle growth of lettuce seedlings with 50% suppression at 0.12 mg dry leaves/mL of agar. Caffeine concentration in tea samples analyzed by high-performance liquid chromatography (HPLC) varied from 20.7 to 38.2 µg/mL of dry leaves. The specific activity (EC50 value) of pure caffeine was 75 µg/mL, and the highest total activity of caffeine estimated in Vinatea-green tea was 0.51 [no unit]. Caffeine from green and oolong tea may be considered as one of the contributors to the inhibitory activity of the crude extract. Moreover, the phytotoxicity of pure caffeine and aqueous tea extracts was highly selective on the growth of different plant species. The concentration of caffeine detected from tea farm soil ranged from 0.137 to 0.145 µg/g soil. The results indicated that caffeine might be considered as a promising allelochemical from Vietnamese tea and can be a good candidate for weed management.
Highlights
The excessive use of chemical herbicides has caused some environmental pollutions and threatened human health in some extreme situations
The present study revealed that caffeine could be partly radicle growth of lettuce seedlings
The present study revealed that caffeine could be partly responsible responsible for the phytotoxic effect of tea extracts, and Vinatea-green tea may be considered as a potential material for future weed management
Summary
The excessive use of chemical herbicides has caused some environmental pollutions and threatened human health in some extreme situations. The increasing number of herbicide-resistant weeds due to the indiscriminate use of synthetic herbicides could damage the ecosystem over a long period [1,2,3]. Allelopathic species and allelochemicals have been utilized as alternative weed management strategies in sustainable agricultural practices [4,5,6]. There are increasing possibilities for developing bio-herbicides from plants that could be used for weed control to minimize the heavy reliance on synthetic herbicides [7]. The reason for the current trend in the exploitation of allelopathic plants and allelochemicals could be due to the potential of finding new, environmentally friendly bioactive compounds [10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
