Date of Completion


Document Type


Degree Name

Bachelor of Science in Biochemistry


Streptococcus pneumoniae, Origanum vulgare, flavonoids, phenolic acids, NanA enzyme


Pneumonia is one of the major causes of mortality in the Philippines, and doctors all over the world use antibiotics to treat the bacteria-caused pneumonia, specifically Streptococcus pneumoniae, which is the most prevalent type of pneumonia. Antibiotics are considered as the primary treatment for pneumonia but due to the development of antibiotic resistance they are becoming less effective. Enzyme inhibition is a crucial part of drug discovery but studies regarding potential inhibitors of Streptococcus pneumoniae, especially NanA are limited. With this, the study focused on finding possible inhibitors of the NanA enzyme of S. pneumoniae since it is vital for activating bacterial pneumonia. The main goal of the study was to determine the possible inhibitory effect of Origanum vulgare flavonoids and phenolic acids against the NanA enzyme of Streptococcus pneumoniae. This was made possible through the standard inhibitor chlorogenic acid since it exhibited antibacterial properties against the NanA enzyme of Streptococcus pneumoniae and thus, it was used as a reference for determining the phytochemicals which could have the ability to inhibit the NanA enzyme of S. pneumoniae Docking investigations using UCSF-Chimera reveals that out of the 19 phytochemicals (flavonoids and phenolic acids) of Origanum vulgare four (4) exhibited a more negative binding energy than the standard inhibitor. Lithospermic acid has the most negative binding energy and has the most number of molecular interactions with the NanA enzyme of S. pneumoniae. According to the Swiss ADME results, none of the four phytochemicals can cross the gastrointestinal tract or blood brain barrier, hence they should not be administered orally, but rather through other routes of administration. The ProTox-II toxicity prediction asserted that all four phytochemicals might be harmful if administered orally, with lithospermic acid having the most severe toxic impact if ingested. The toxicity results even emphasize the fact that if these phytochemicals are to be utilized as a Streptococcus pneumoniae NanA enzyme inhibitor, they should not be administered orally. In conclusion, it is suggested for future researchers to try to use different grid dimensions in search for other active sites of NanA enzyme. Furthermore, future researchers are encouraged to conduct in vivo and in vitro studies to assess the potential inhibitory impact of Origanum vulgare phytochemicals. Exploring the derivatization of oregano flavonoids and phenolic acids to provide a greater negative binding energy with the NanA enzyme receptor is also recommended. The last recommendation is to assess the acute inhalation toxicity of Origanum vulgare phytochemicals in order to determine their safeness if the inhibitors are ever administered by inhalation.

First Advisor

Walter Aljhon Espiritu