Peptides and low molecular weight polypeptides of Azadirachta indica seeds as new weapons against cancer cells and superbugs

Abstract

BackgroundIn Ayurvedic practice, neem is an immensely important medicinal plant that's been part of traditional medications dating back to ˂ 5000 years. Its botanical name being A. indica while it is known as Nimba in Sanskrit. Prior to written records, all the parts of neem were used to treat and cure various ailments, infections, fevers, etc. Such wide range of application has led to it being termed “the village pharmacy.” The current study reports for the first time extraction and biological activity evaluation of these AMPs and polypeptides derived from the seeds of A. indica. Materials and methodThe present study intends to be the first to evaluate the antimicrobial and antitumoral properties of peptides and polypeptides on cancer cell lines from the total protein extracted from neem plant seeds by means of cell and molecular biology approaches. Protein extraction and precipitation was performed applying our optimized/standardized protocols. The antimicrobial activity was assayed efficiently using PAG-ADA method. The anticancer property of the extracted protein was detected by MTT assay, while MALDI-TOF/TOF and FTIR were performed to characterize the structure of these AMPs and polypeptides. ResultsTwo standardized protein extraction procedures were employed and the protein obtained from these two procedures were 262.67 ± 6.12 and, 248.7 ± 9.49 mg/g of seeds, respectively. Our study reports two novel antimicrobial peptides, and four polypeptides extracted from the dried seeds of A. indica. Further, we confirmed the bactericidal activity of the peptides and polypeptides extracted from A. indica seeds using PAG-ADA techniques against six different human pathogens. Remarkably high zone of growth inhibition against MRSA (30.0 ± 1.52) mm was noted. On the other hand, the total protein extracted possessed excellent anticancer activity with low IC50 values of 33.46 ± 2.63 and 20.83 ± 1.60 μg/mL against HeLa cells and 6.94 ± 0.10 and 6.87 ± 0.90 μg/mL against BT549 cell lines at 24 and 48 h, respectively. ConclusionsAMPs and polypeptides extracted from seeds of the medicinal plant A. indica exhibited bactericidal activity against different bacterial pathogens. In addition, the extract possessed good anticancer activity against the cervical cancer and breast cancer cell lines. Therefore, these promising findings pave the way for identification of plant-based bioactives responsible for the anticancer and antimicrobial attributes.