Every week, some of our senior researchers in each department at ASDRP give public seminar presenting the current state of the field, and disseminating how their research at ASDRP fits into the broader context of the frontiers of modern science and engineering. Colloquia are public events, and anyone can join. Simply click the Google Calendar link to add the event to your calendar.
Department of Chemistry, Biochemistry & Physics
Fridays @ 8:00 - 9:00 PM PST
Friday, February 5, 2021
Comparative singlet oxygen photosensitizer efficiency of berberine, rose bengal, and methylene blue by time course nuclear magnetic resonance (NMR) monitoring of a photochemical 4+2 cycloaddition endoperoxide formation .
Berberine, a natural product alkaloid, has been shown to exert biological activity via in situ production of singlet oxygen, a highly reactive oxygen species when photo irradiated. Berberine utilizes singlet oxygen in its putative mechanism of action, wherein it forms an activated complex with DNA and photosensitizes triplet oxygen to singlet oxygen to specifically oxidize guanine residues, halting cell replication, leading to cell death. This has potential application in photodynamic therapy, alongside other such compounds, which also act as photosensitizers and produce singlet oxygen in situ. In this study, berberine's singlet oxygen production was compared against two known photosensitizers, methylene blue and rose bengal, to determine berberine’s efficacy as a singlet oxygen photosensitizer. Singlet oxygen production can be monitored by trapping the reactive oxygen species with a diene via a 4+2 Diels Alder-like cycloaddition reaction, and resulting endoperoxide can be quantified using 1H nuclear magnetic resonance (NMR) spectroscopy. The quantification of singlet oxygen production can direct the future synthesis of berberine analogs and identify medicinally significant singlet oxygen photosensitizers.
Sophie P., Carlmont High School
Njoo Research Group
Organic, Medicinal Chemistry