Botanical Extracts and Compounds of Castanea Plants and Methods
of Use: US20190125818A1 - The United States Patent Evaluation
Authors: dos Santos Tatiane Batista , dos Santos Gomes Denilson , dos Santos Neto Agenor Gomes , do Amorim Costa Gaspar Lívia Maria , Droppa-Almeida Daniela 
Published: June 2023

Background:

Bacterial infections are increasingly difficult to combat, which makes them
a threat to public health on a global level. Staphylococcus aureus is considered one of the main causes
of infections in hospitals, as it has a variety of virulence factors, as well as is able to produce bacterial
biofilms, which, consequently, bring numerous damages to public health as a result of increased
resistance to conventional antibiotics and a longer hospital stay. Therefore, the use of compounds extracted
from medicinal plants is a potential pharmaceutically acceptable target, as they do not have
toxicity and the potential to disrupt biofilms produced by Staphylococcus aureus already evidenced,
thus revealing their relevance to our study.

Objective:

The objective of this work was to perform a critical analysis of a patent with natural extracts
against bacterial biofilms found in the United States Patent and Trademark Office (USPTO) database,
to map the possible bioactive compounds that may serve as potential future antimicrobial drugs.

Methods:

A technological survey was carried out to verify existing patents using natural extracts with
anti-biofilm potential. For this, it was searched with the keywords: Botanical extracts AND biofilms;
which were performed in the United States Patent and Trademark Office (USPTO) database. Thus, the
selected patent used a non-aqueous extract partitioned and vacuum-contracted, subsequently lyophilized
for assays with antimicrobial potential. Because of this, a patent was analyzed regarding its chemistry,
and biological activity, followed by a critical analysis of the technology proposed in the invention.

Results:

When using the keywords Botanical extracts AND biofilms in the USPTO, it was possible to
find twenty-two inventions; however, only four patents in the USPTO were in agreement with the
proposal of the natural extract having antimicrobial activity and an anti-biofilm potential, of which
two belonged to the same applicant with similar proposals. The key point of this invention was to enable
the compounds of the Castanea sativa plant and its methods of obtaining the extract to present a
significant antimicrobial action associated or not with antibiotics, promoting the development of new
therapies against bacterial infections capable of disrupting biofilms. The invention developed a
methodology for extracting Castanea sativa, in which pentacyclic triterpene compounds were found
mostly in its leaves. Whereas for the extraction, the crude methanol extracts called extracts 224 from
the ground leaves were made by maceration, filtered, combined, concentrated under pressure in rotary
evaporators, and lyophilized. After that, they were resuspended in water and partitioned in succession
with hexane, ethyl acetate, and butanol. The most active refined partition was the 224C extract
with the solvent ethyl acetate, which was subjected to further fractionation using silica column chromatography.
Resulting in the most refined extract, which was 224C-F2, capable of acting directly on
the quorum sensing of bacteria, mainly Staphylococcus aureus, blocking the translation of RNAIII,
including a series of exotoxins. Regarding the antimicrobial capacity against Staphylococcus aureus,
it presented Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration
(MBC) of 1.56 μg/mL-1 and > 100 μg/mL -1, respectively.

Conclusion:

Given the analyzed patent, it was possible to verify the importance of alternatives to reduce
the impact of bacterial biofilms, which causes damage to industries in general and to health. From
this, the invention analyzed has a promising proposal with antimicrobial potential focusing on the great
impact of bacterial biofilms. Therefore, natural extracts with antibiofilmic potential can help to minimize
the economic losses caused to health due to these multidrug-resistant microorganisms with different
virulence mechanisms.