Formulation of Neem and Echinacea Gel for Oral Health Along With the Evaluation of Antimicrobial, Cytotoxic, Anti-inflammatory, and Free Radical Scavenging Activity: An In Vitro Study

Abstract

Background Herbs have been used in medical practice for centuries and continue to play a significant role in modern complementary and alternative medicine. Phytochemicals in these herbs possess strong antioxidant and anti-inflammatory properties, which are beneficial in targeting oral health issues, such as dental plaque, gingivitis, and oral microbial infections. As research progresses, the challenge remains to translate these natural compounds into safe, effective, and accessible treatments for a wide range of diseases. Aim The aim of this research was to formulate the neem and echinacea gel along with the evaluation of antimicrobial, anti-inflammatory, free-radical scavenging activity, and cytotoxic potential. Materials and methods The neem and echinacea gel was prepared using a concentrated powdered mixture of neem and echinacea (5 grams each) to which 100 ml of distilled water was added, and the mixture was boiled for 30 minutes at 60°C. The 10 ml concentrate was mixed with 20 ml of a carbopol and carboxymethyl cellulose (CMC) mixture and mixed thoroughly, which resulted in neem and echinacea gel. Then, the antimicrobial, anti-inflammatory, cytotoxic potential, and free-radical scavenging activity of the gel were evaluated. The data obtained were statistically analyzed with the help of a paired t-test, where a p-value of less than 0.05 was considered statistically significant. Results The antimicrobial assay showed that neem and echinacea gel at the concentration of 100 micrograms showed a greater zone of inhibition against Staphylococcus aureus (3.15 ± 0.26), Streptococcus mutans (2.48 ± 0.45), Enterococcus faecalis (2.89 ± 0.15), and Candida albicans (4.28 ± 0.87). The cytotoxic test revealed that even at an 80 µg concentration of the extract, more than 70% of the nauplii were vital, which indicated that the gel was not cytotoxic. The highest anti-inflammatory activity (78.39 ± 1.82) of the gel was seen at 50 micrograms when compared with diclofenac sodium (73.16 ± 1.80). The free radical scavenging activity showed that the 2,2-diphenyl-1-picrylhydrazyl (DPPH) absorbance of the neem and echinacea extract was highest at 50 micrograms. Conclusion The combination of neem and echinacea extract-based gel possessed high antimicrobial and anti-inflammatory activity when compared with standard drugs, such as amoxicillin and diclofenac sodium. The antioxidant activity of the gel was equal to butylated hydroxytoluene (BHT), and also the gel has a low cytotoxic potential even at its higher concentrations. Hence, the gel can be used as a natural remedy with minimal side effects, making it a valuable alternative to chemical agents.

Keywords: antimicrobial activity in natural products; azadirachta indica (neem extract); echinacea; generalized periodontitis; local drug delivery agents.

Figure 1. Neem and echinacea extract

The above image depicts the thickened crude extract of neem and echinacea after boiling for 30 minutes at 60°C.

Figure 2. Neem and echinacea gel

The 10 ml concentrate of neem and echinacea extract was mixed with the carbopol and carboxymethyl cellulose (CMC) mixture to obtain neem and echinacea gel.

Figure 3. Antimicrobial activity of neem and echinacea gel against Staphylococcus aureus

The antimicrobial activity was seen against Staphylococcus aureus in the agar medium with different concentrations of neem and echinacea gel (25 µg, 50 µg, and 100 µg) along with the control (amoxicillin).

Figure 4. Antimicrobial activity of neem and echinacea gel against Enterococcus faecalis

The antimicrobial activity was seen against Enterococcus faecalis in the agar medium with different concentrations of neem and echinacea gel (25 µg, 50 µg, and 100 µg) along with the control (amoxicillin).

Figure 5. Antimicrobial activity of neem and echinacea gel against Streptococcus mutans

The antimicrobial activity was seen against Streptococcus mutans in the agar medium with different concentrations of neem and echinacea gel (25 µg, 50 µg, and 100 µg) along with the control (amoxicillin).

Figure 6. Antifungal activity of neem and echinacea gel against Candida albicans

The antifungal activity was seen against Candida albicans with different concentrations of neem and echinacea gel (25 µg, 50 µg, and 100 µg) along with the control (fluconazole).