Abstract:
Background: Although processed tea offers numerous nutritional benefits, it may contain
pesticide residues due to the excessive use of pesticides in tea plantations. As a result, tea as a
drink may adversely affect the human health. Therefore, it is important to find a suitable non-toxic
substitute for tea that replicates the full range of nutritional compounds found in tea. In this regard,
Adhatoda could serve as a potential substitute, as it contains a similar nutritional profile and
requires no pesticides for plantations.
Objective: To compare the content of pesticide residues on Camellia sinensis (Tea) and Justicia
adhatoda (Adhatoda)
Methods: Properly shade-dried, blended Adhatoda leaves and 10 commercial tea samples from
Sri Lankan market were taken for the analysis of pesticide residues. The analysis (EN
15662:2018) was done using Liquid Chromatography system (Agilent 1260 INFINITY II)
coupled with Tandem Mass Spectrometer (LC-MSMS), Agilent 6470LC/TQ. Agilent ZORBAX
Eclipse Plus C18 (2.1x150 mm, 3.5-Micron) column was used for separation. The scan results
were evaluated with 246 pesticides in the database.
Results: Eight tea samples out of 10 showed the presence of pesticide residues at ppm level
(0.071-0.176 ppm). The identified pesticides include 2-methyl-4-chlorophenoxyacetic acid
(MPCA), Diuron, profenofos, teboconazole, chlorpyrifos, propiconazole, and fenbuonazole.
MCPA was detected in 5 tea samples. Diuron was detected in 4 tea samples. Both MCPA and
diuron were detected in two tea samples. Pesticide residues were not detected in Adhatoda.
Conclusions: The Majority of tea samples indicated the presence of pesticide residues. Some of
the detected pesticides in tea samples exceed the maximum residue limit accepted by Sri Lankan
tea board standards (>0.1 ppm) and considered as not suitable for human consumption according
to European Union regulations. Adhatoda, contain high nutritional value such as tea and free of
pesticide residues compared to tea.
