Current Status,Distribution, and Future Directions of Natural Products against Colorectal Cancer in Indonesia: A Systematic Review

In 2020, an estimated 19.3 million new cancer cases and nearly 10 million cancer deaths have occurred worldwide, with colorectal cancer ranking as the third most frequently diagnosed (10.0%). Several attempts have been conducted against cancer, including surgery, radiation, monoclonal antibodies, and chemotherapy. Many people choose natural products as alternatives against cancer. These products will not only help in human life preservation but also work as a source of up-to-date information, leading people away from incorrect information. We discuss the current status, distribution, and future implications of protecting populations with natural products as an alternative against colorectal cancer in Indonesia. Thirty-eight studies were included in this review for data extraction. The distribution of natural products in Indonesia that have potential activity against colorectal cancer cells was predominated by terpenoids, followed by phytosterols, phenolics, alkaloids, and polyisoprenoids. The type of cell line utilized in the cytotoxic activity analysis of natural products was the WiDr cell line, followed by HT-29 cells and HCT-116 cells. This review showed that MTT in vitro assay is a general method used to analyze the cytotoxic activity of a natural product against colorectal cancer cells, followed by other in vitro and in vivo methods. The systematic review provided predictions for several secondary metabolites to be utilized as an alternative treatment against colorectal cancer in Indonesia. It also might be a candidate for a future co-chemotherapy agent in safety, quality, and standardization. In addition, computational methods are being developed to predict the drug-likeness of compounds, thus, drug discovery is already on the road towards electronic research and development.     

Analysis of the stochastic variation in LTQ single scan mass spectra

A better understanding of the scan-to-scan signal intensity variation can lead to more sophisticated algorithms for database searching and de novo peptide sequencing using single scan mass spectra. In this study, we systematically studied the variation in relative intensity of m/z values in the single scan product ion mass spectra (MS2) derived from five representative precursor ions (MS1) collected using an LTQ linear ion trap under constant flow direct infusion conditions with peptide concentrations held constant. We applied a matching algorithm based on a pair hidden Markov model to align the peaks from each scan belonging to the same m/z value prior to assessing the signal intensity variation. The most significant single contributor to scan-to-scan signal intensity variation for high abundance ions was centroider error. Our study also showed that the variation in signal intensity is higher than what would be expected if the ion statistics derived from the dual geometry electron multiplier detector followed a Poisson distribution.