Background: Species of crocodiles and cockroaches can withstand high radiation, reside in unsanitary
conditions, thrive on germ-infested feed, and are exposed to heavy metals, yet they are not reported to
develop cancer. It has been postulated that such species have mechanisms to defend themselves against developing
cancer. Here, selected species have been tested for potential cytotoxicity against selected cancer cell lines.
Methods: In this study, various species of vertebrates and invertebrates were procured including Columba livia,
Gallus gallus domesticus, Varanus salvator, Cuora kamamora amboinensis, Reticulatus malayanus, Oreochromis
mossambicus, Rattus rattus, American bullfrog, Donax sp., Polymesoda coaxans, Tenebrio molitor,
Lumbricus terrestris, Blatta lateralis, Grammostola rosea, and Penaeus monodon. Species were dissected and
their organ lysates/sera/haemolymph were prepared. Cytotoxicity assays were performed using Prostate Cancer
cells (PC3), Henrietta Lacks cervical adenocarcinoma cells (HeLa) and human breast adenocarcinoma cells
(MCF7) as well as human keratinized skin cells (Hacat), by measuring lactate dehydrogenase release as an indicator
for cell death. Growth inhibition assays were performed to determine the effects on cancer cell proliferation.
Liquid Chromatography-Mass Spectrometry (LC-MS/MS) was performed for molecular identification.
Results: The results revealed that body lysates of Polymesoda coaxans demonstrated more than 99% growth
inhibition of all cancer cell lines tested but not on normal Hacat cells. More importantly, the serum of M. reticulatus
abolished growth and produced cytotoxicity. Hence these samples were subjected to Liquid Chromatography-
Mass Spectrometry (LC-MS/MS), which detected 81 small molecules and putatively identified 20 molecules
when matched against the METLIN database. Out of 1094 peptides, 21 peptides were identified, while
1074 peptides were categorized as novel peptides. Based on properties such as peptide amino acid composition,
binary profile, dipeptide composition and pseudo-amino acid composition, 306 potential peptides were
Conclusion: To our knowledge, here for the first time, we report a comprehensive analysis of sera exhibiting
cytotoxicity against cancer cell lines tested and identified several molecules using LC-MS/MS.