Artificial intelligence (AI)
The World Health
Organisation claims that plants are capable of producing secondary metabolites.
These are aromatic chemicals that are essential to plants for defence against
insects, microbes, and other entities. Plants possess therapeutic effects due to
these protective compounds. According to World Health Organisation statistics,
almost 80% of people worldwide still use traditional medicines.
The use of traditional
medicines for common disorders has been greatly aided by the concoctions made
from a combination of several plants in the form of aqueous extract. Fruits
from the plants Helicteresisora and Piper longum are frequently utilised as
antibacterial agents.
Spices like piper longum are
widely used in Vietnam, Malaysia, India, and East Africa. Its fruit has long
been used to cure bacterial illnesses such as constipation, diarrhoea, cholera,
asthma, and gastrointestinal issues. It smells strong and disagreeable,
although it is less fragrant and acrider[1]. Tannins, steroids, and phenol are
some of the components that give it its antibacterial and anti-inflammatory
qualities. In water extract, Tharakan and Madhavan (2017)[2] discovered several
water-insoluble alkaloids with distinct modes of bacterial inhibition,
including piperine and personal in piperlonguminine. For instance, piperine
blocks bacteria's efflux pump.
Another plant employed in
this experiment is Helicteresisora, a big shrub that is typically found in arid
woodlands. It's a
Figure 1 shows
bacterial cell wall composition
long, slender fruit with
rounded edges to its surface[3]. It is employed in conventional medicine to
combat bacterial illnesses. Helicteresisora is useful and curing for
hypolipidaemic, anti-oxidant, hepatoprotective, and cardiotonic actions,
according to research by Sharma and Chaudhary (2016)[4] . Additionally, it has
been noted that the root juice of Helicteresisora is useful in treating fever
(induced by Salmonella bacteria), asthma (caused by bacteria that cause
Mycoplasma pneumonia and MRSA pneumonia), cough (caused by Bordetella
pertussis)[5].
Helicteresisora has
phytochemical components such Glyceriods like amygdalin, Rosmarinic Acid,
phlorotannins, and saponins, which are vital for plants' antibacterial
activity. Additional non-water soluble phytochemical substances, such as
alkaloids and anthraquinones in the aqueous extract of Helicteresisora, were
also found in another study (Kumar et al. 2007 Heading Abstract)[6].
Piper longum and
Helicteresisora had different effects on gram-positive and gram-negative
bacteria[7,8]. Some possible mechanisms to inhibit bacterial growth by
phytochemicals are interacting with membrane protein and disintegrating the
cell membrane, coagulating cell content, inhibiting DNA gyrase, and inhibiting
protein biosynthesis[9].
Staphylococcus epidermidis
causes inflammation, sinus infection and wound infection. My grandfather has
been a victim of sinus infection, and most of sinus tissue have been badly
damaged. It is a gram-positive bacterium with a thicker peptidoglycan cell
wall.
Escherichia coli is a Gram-negative bacteria with thin cell
walls of peptidoglycan and an outer membrane with lipopoly saccharide and causes Stomach pain, Vomiting, Diarrhea,
etc[10]. Stomach problems have been common in my family, thus it encouraged me
to explore this bacteria.
My personal career goal is
to become a biotechnologist, and our class experiments inspired me to measure
the herbs' inhibitory zone against gram-positive and gram-negative bacteria in
order to learn more about their biological importance. The measurement of the
inhibitory zone's diameter was done using a dependable, conventional technique.
Furthermore, the Soxhlet (hot) extraction method is precise in extracting
antibacterial phytochemicals and the extraction is performed in aqueous
solution. It is a continuous process utilizing the principle of siphoning and
reflux and requires less time than another extraction process like maceration
and percolation. It produces higher extract concentration with better-quality
extract without changing the chemical properties of active constituents. Five
concentrations of plant extract would be enough to produce reliable results.
The higher the concentration, the more antibacterial components would be
present, leading to a faster reaction rate (killing of bacteria). This would
give a relatively large inhibition zone diameter and vice versa. Other
extraction methods like reflux extraction or decoction can be used, but they
consume more time and have some water-soluble impurities[11].
2.Literature review
The findings of the research conducted
by Mahajan and Itankar 2020[12] confirm this view. Helicteres isora differed
significantly in its ability to inhibit gram-positive and gram-negative
bacteria's development, and that it had a greater impact on gram-positive stain
depending on the kind of extract used in the experiment. Compared to aqueous
extract and other organic solvent extracts, ethanolic extract had the largest
variation in the zone of inhibition, indicating that the extraction solvent has
an impact on the assessed antibacterial activity. In contrast, Tambekar et al.'s (2008) research
demonstrates that an aqueous extract exhibited the largest inhibitory zone and
the highest yield, indicating that the extract selection was accurate.
Gram-positive bacteria were equally or more affected by Helicteresisora.
Accepting the null hypothesis, it may be said that there was no discernible
difference between the gram-positive and gram-negative bacteria in this
Helicteresisora experiment. High plant extract concentration values require
more investigation because they appear to have a stronger impact on gramme
negative bacteria compared to gramme positive bacteria, which runs counter to
every finding in the literature review.
3. Method
A.
Hot
Extraction method (For the extraction of leaves)
Gather 60±0.01 gram of each type of plant. Use a mortar
and pestle to crush, and a mixer grinder to grind into a fine powder. Put
50±0.01g of leaf powder in 170±0.5ml of petroleum ether to defat it. To prevent
the liquid from evaporating, pack it snugly and cover it with cling wrap.
Spread the treated powder on the paper to allow the petroleum ether to
evaporate after a full day. Apply Whatman filter paper to the porous thimble to
prepare it. Weigh out 15± 0.01g of powder in the porous bag, then set it within
the device's main chamber. Fill the flask with 200±0.5 ml of distilled
water. Connect the extractor's tubes
carrying the cold water supply and the condenser.
The moment at which the colour of the solution in the
thimble becomes entirely transparent at 90°C indicates that the plant extract
has been extracted fully after around 16 hours of heating. Using a spatula,
transfer the distillation flask solution into the beaker. To obtain dry
extract, use a water bath set at 80°C to evaporate the extraction liquid. Put a
label on it.
B.
Stock
solution preparation
To create 100 mg/ml of stock solution, add 1± 0.01g of
extract to 10±0.1ml of distilled water in a small bottle and mix gently. Fold
the foil paper over the tiny bottle. Put the bottle in the sonicator to get the
extract dissolved.
C.
Antibacterial
Testing
Well Diffusion Method and inhibition zone Measurements
a. Well Diffusion Method
Transfer
the Agar media to each agar plate evenly and leave it under laminar air flow
for 2 hours to settle. Take the Sterile Swab, put it into the bacterial
culture, and then rub the swab in the agar plate (use bacterial culture, which
is in stationary phase, to have maximum and equal bacterial population). Create
the well using the sterile borer (sterilized using Flame) diameter of - 6mm.
Using a micropipette, add 40±0.8 µl of 5 Different Concentrations of extract. (Change the
Micro-tip after every trial). Seal the plates partly and Put them in the
incubator for 72 hours at 25°C. After 72 hours, measure inhibition zone (Diameter) using inhibition
zone measuring scale.
b.
Iinhibition zone
Measurements
Small white circular bacteria colonies were visible after
the incubation. Some inhibition zone had dark yellowish color for circles, and
others had light circular yellowish color.
The color change was visible in solvent in soxhlet
extraction before and after plant extraction. The color from transparent
changed to dark black color for both plants
Fig. 3 Inhibition zone for Staphylococcus epidermidis for trial
four against Helicteresisora
4.Results and discussion
Effect of increasing concentration of Helicteresisora on
inhibition zone measurement in mm (± 0.5mm) against Staphylococcus epidermidis
and Escherichia coli showed in Table 1.
Table 1: Effect of increasing concentration of in gram
positive and gram negative bacteria.
Graph 1 shows logarithm curve for Average inhibition zone
for Helicteresisora against Staphylococcus epidermidis and Escherichia coli
(Error bars are standard deviation)
Table 3 shows the
rate change (gradient) for Helicteresisora
from graph 1 calculated by GDC
The graph displays a logarithmic increase in the
Helicteresisora zone of inhibition, with an initial sharp gradient and a later
less steep gradient. The rate change decreases with increasing extract
concentration. At higher extract concentrations, rate change is very low (Table
3) as the zone of inhibition is reaching plateau, suggesting a saturation point
(Maximum strength of extract).
The graph showed Helicteresisora produces greater
inhibition zone against Staphylococcus epidermidis than against Escherichia
coli at lower extract concentrations. At higher concentrations greater
inhibition zone was produced against Escherichia coli than against Staphylococcus
epidermidis. Thus, as plant extract concentration increases, greater inhibition
zone is produced.
The same inhibition zone value for both bacteria by
Helicteresisora is observed in graph 1 at the intersection point of the graph.
The error barsin the graph represent the standard
deviations that mostly overlap, giving insignificant differences.This is
because Gram-positive bacteria are easy to kill as they have porous
peptidoglycan layer, allowing easy phytochemical component’s penetration. However, gram-negative bacteria have additional
impermeable outer membraneswhich resist antibacterial components at lower
concentrations to enter bacteria.
Moreover, the poorly water-soluble
components like alkaloids, glycoside, and flavonoids, when diluted with water,
wouldbe present in very less quantity, leading to lower value of inhibition
zone on Escherichia coliat low concentration. The control value is not included
logarithmic curve as the curve does not
passes origin (0,0). The total mass obtained of Helicteres isora after
extraction was 5.01±0.01gm
Effect of increasing concentration of Piper longum on
inhibition zone measurement in mm (± 0.5mm) against Staphylococcus epidermidis
and Escherichia coli shown in Table 4
Table 4: Effect of
increasing concentration of Piper lingum in Gram positive and Gram negative
becteria.
Graph 2 shows logarithm curve for average inhibition zone value
for Piper longum against Staphylococcus epidermidis and Escherichia coli
Table
5 shows the rate change for Piper longum from graph 1 calculated by GDC
The rate change (table 5) for the zone of inhibition zone
for Escherichia coli was consistently higher than that of Staphylococcus
epidermidis, indicating a logarithmic rise in the zone of inhibition by Piper
longum with a steep gradient early but a less steep gradient later.
In graph two, at high concentrations, Piper longum is
more effective at Escherichia coli than Staphylococcus epidermidis.
The literature value of P.D. Lokhande et al. 2007[13]
suggests that Piper longum has an equal or more significant effect on
gram-positive bacteria than on gram-negative bacteria. The error bars in Graph
2 do not overlap for lower values. However, theyoverlap at high values. It can
be concluded Piper longum shows significantly different result only for lower
plant extract concentration, and for high extract concentration, it is
insignificant.
It is easy for phytochemicals to penetrate in gram
positive than in gram negative bacteria, due to membrane structure. More
research needs to be done for high plant extract concentration values, as they
show greater effect on gram negative bacteria than on gram positive bacteria
which contradicts most literature review, and structural aspects.
The total extract mass obtained of Piper
longum was 3.98±0.01gm
Since it is not evident from the graph, this statistical test was used
to investigate the statistical difference of the 100 mg/ml extract
concentration of Helicteresisora and Piper longum on Staphylococcus epidermidis
and Escherichia coli (with reference to graphs 1 and 2). Whether or not the
outcome is statistically different at other concentrations is made evident by
the overlapping error bars.
Figure 4 Test for Helicteresisora
on Staphylococcus epidermidis and Escherichia coli
Figure 5 Test for Piper
longum on Staphylococcus epidermidis and Escherichia coli
According
to a one-way ANOVA analysis, the F-statistic value for both plants (Figures 4
and 5) has a p-value larger than 0.05 (5% Significance Level), indicating that
there is no statistically significant difference in the mean inhibition zone of
Helicteresisora against Escherichia coli and Staphylococcus epidermidis. The
same is true for Piper longum. Since there aren't many changes between the two
microorganisms.
Graph 3 shows
antibacterial activity of both plant
5. Conclusion
Helicteresisora appears to be more efficient against
Escherichia coli and Staphylococcus epidermidis than Piper longum, as indicated
by a graphical representation. Flavonoids, among other phytochemicals, disrupt
cell membranes and prevent the formation of cell envelopes and nucleic acids.
Because of the great affinity of phenol's hydroxyl group for binding proteins,
it can easily penetrate and damage bacterial membranes before harming the
cytoplasmic membrane[14]. According to other studies, the dry fruit of
Helicteresisora has a flavonoid content of 2.33±0.32 (± standard deviation) mg
per gram and a phenol content of 4.95±0.01 mg per gram. Piper longum also had a
total flavonoid content of 0.07±0.02 mg per gram and a total phenol content of
0.93±0.003 mg per gram. This says Compared to Helicteresisora, Piper longum has
a lower content of flavonoids and phenols in plant extract, which results in a
weaker antibacterial action as determined by the inhibitory zone. Through graph
3, it can be concluded that the inhibition zone of Helicteresisora and Piper
longum against Staphylococcus epidermidis and Escherichia coli shows
significant differences as most standard deviation values do not overlap
(comparing red dotted line with yellow, and blue line with grey).