In humans, animals,
and agriculture, parasitic nematode
infection
is a very serious issue. Many drugs are being used to control nematode
infections. Owing to toxicity and nematodes’ resistance to
the available drugs, special attention is required to synthesize new
drugs that are environmentally friendly with high-level efficacy.
In the present study, various substituted thiazine derivatives (1
to 15) were synthesized, and the structures were confirmed by infrared,
proton (1H), and 13C NMR spectroscopies. The
nematicidal potential of the synthesized derivatives was characterized
using Caenorhabditis elegans (C. elegans) as a model organism. Among all synthesized
compounds, 13 (LD50 = 38.95 μg/mL) and 15 (LD50 = 38.21 μg/mL) were considered the most potent compounds.
Most compounds showed excellent anti-egg-hatching activity. Fluorescence
microscopy confirmed that compounds 4, 8, 9, 13, and 15 displayed
a high apoptotic effect. The expressions of gst-4, hsp-4, hsp16.2,
and gpdh-1 genes were high in affected (treated with thiazine derivatives) C. elegans in comparison with normal C. elegans. The present research revealed that modified
compounds are highly effective as they showed the gene level changes
in the selected nematode. Due to structural modification in thiazine
analogues, the compounds showed various modes of action. The most
effective thiazine derivatives could be excellent candidates for novel
broad-scale nematicidal drugs.