Centella asiatica (Bao-bog, Pennywort, Gotu kola) is used as a traditional drug widely in Asia. C. asiatica crude extracts showed excellent potential in-vitro but less or no in-vivo activity due to their poor lipid solubility or improper molecular size or both, resulting in poor absorption, poor dosing and poor bioavailability. The Bovine serum albumin (BSA) can attract macromolecular and carry wide variety of molecule. So this research was aimed to develop C. asiatica extract-loaded BSA nanoparticles (CBNP) to improve bioavailability. CBNP was prepared by the desolvation method using three different ratio C. asiatica crude chloroform extracts: BSA (1:2, 1:3, and 1:4). The well agar diffusion method was used for evaluating antibacterial activity of CBNP with different concentration (100, 200, and 300 µg/ml) against five food borne pathogens (Escherichia coli ATCC25822, Salmonella enterica Typhimurium U302 (DT104b), S. enterica Enteritidis (human), S. enterica 4,5,12:i:-(human) US clone, and Bacillus cereus). The results showed that the antibacterial activity of CBNP did not show significant different on three different ratio and concentration in all food borne pathogens except S. enterica Enteritidis (human) and B. cereus (P < 0.05). The highest antibacterial active of CBNP was 1.07±0.46 cm against S. enterica Enteritidis (human) on ratio 1:4, 200 µg/ml. The antibacterial activity of CBNP gave almost 2 times higher than free crude C. asiatica chloroform extracts. The modified Folin-Ciocalteu method, Ferric reducing antioxidant potential assay and DPPH assay were used for evaluating antioxidant activity. The highest antioxidant activity represented by the amount of phenolic content of CBNP was 14.59±6.74 µgGAE/mg using ratio 1:2. The amount of phenolic content of CBNP did not show significant different between ratio 1:2 and others (P < 0.05). For Ferric reducing antioxidant potential assay and DPPH assay, crude chloroform extract showed significantly higher activity than CBNP were 1.00 ± 0.15 mmol Fe 2+ /mg and 29.44 ± 8.20 % DPPH radical scavenging respectively (P < 0.05). The entrapment efficiency and loading efficiency of CBNP showed highest value on ratio 1:4 which were 96.94 ± 1.48% and 42.05 ± 5.68% respectively. It's also showed highest in release kinetic in Vitro approximately 12% during the whole period of 6 hours in both artificial gastric and intestinal juice. C. asiatica crude chloroform extract have higher solubility in water than CBNP but CBNP have higher stability in releasing crude chloroform extract. The results indicated that CBNP showed the promising to increase bioavailability of C. asiatica. The statistical analysis was done by ANOVA using SAS software version 9.3.

Nanoencapsulation of Centella asaitica (CA) crude chloroform extract seems to be an attractive approach that may improve drug bioavailability and drug delivery system. In the study, CA extract-loaded gelatin nanoparticles (CGNP) were developed by gelatin one-step and two-step desolvation methods, using three different ratios between CA crude chloroform extract and gelatin (1:2, 1:3, and 1:4 w/w). The antibacterial and antioxidants activities of CGNP and CA were compared. The antioxidant activity of CGNP and CA was evaluated by using DPPH radical scavenging assay and ferric reducing antioxidant power (FRAP) assay. Results showed an enhancement of CGNP antibacterial activity against food borne pathogen. The highest inhibition diameters and FRAP determined from CGNP prepared by one-step at 1:4 ratios (1.03±0.39 cm and 1.23±019 mmol Fe2+/mg dried weight, respectively). However, CGNP was no significant difference in DPPH radical scavenging activity compared to CA. These results provide useful information for developing effective nanoencapsulation of CA as effective natural ingredient.

Bioavailability of active compounds extracted from herbs is generally limited to be adsorbed or expressed to target organisms due to several physical and chemical factors. Nanoparticle encapsulation techniques was developed to carry bioactive macromolecules of Centella asiatica (Buabok) in the form of C. asiatica Extract-loaded Bovine Serum Albumin Nanoparticles (CBNPs) to improve bioavailability. In this study, the antioxidant activities of CBNPs and C. asiatica crude extract were evaluated by using DPPH radical scavenging assay in the simulated gastrointestinal system, including mastication, stomach, duodenum, and ileum conditions to provide the environment which similar to in vivo system in terms of chemical and physical parameters. CBNPs were prepared by mixing of C. asiatica crude extract and BSA at different ratio of 1:2, 1:3, and 1:4. The results showed that the highest antioxidant activity of CBNP was observed when the ratio of crude extract and BSA at 1:2 was used at pH 2.0 or in the simulated stomach condition. The denaturation or unfolding of BSA in the simulated stomach occurred when pH was low could lead to the release of active compounds at certain area in gastrointestinal system.