Chitosan is a modified carbohydrate polymer obtained from the deacetylation of chitin and has good and unique characteristics, including its ability to be biodegradable, biocompatible, and nontoxic. The purpose of this study was to manufacture chitosan from freshwater lobster shells formulated in the form of a hand sanitizer gel that is stable and determine its antibacterial activity against Escherichia coli and Staphylococcus aureus. The chitosan obtained was then made into hand sanitizer gel preparations with concentrations of 1.5%, 3%, and 4.5%, and then an evaluation test was carried out on the hand sanitizer gel preparation, as well as antibacterial testing against E. coli and S. aureus. The results showed that the hand sanitizer preparation in the organoleptic test did not show any change in odor, shape, and color. The homogeneity test showed the absence of coarse granules. The results of the pH testing confirmed that the pH of the preparation was still within the permitted criteria limits. The dispersion test also showed the average is in the range of 5-7 cm so that the formula meets the requirements. The results of the antibacterial activity test of the chitosan hand sanitizer gel showed that it can inhibit E. coli bacteria with the best inhibition zone obtained at a concentration of 4.5% at 8.8 mm and S. aureus with the best inhibition zone at 10 mm.

Skin disease was a disease that attacked the surface of the body, and was caused by various agents, one was bacteria. One of the plants that had antibacterial activity was jengkol leaf (Archidendron pauciflorum Benth.) I.C. Nielsen because it contained compounds that had antibacterial properties that had previously been studied by other researchers against Staphylococcus aureus and Escherichia coli bacteria. So that researcher was interested in researching on the antibacterial activity of jengkol leaves (Archidendron pauciflorum Benth.) I.C. Nielsen against Staphylococcus epidermidis and Propionibacterium acnes. Fresh Jengkol leaves were processed into simplicia and extracted using 96% ethanol. Phytochemical screening was carried out on simplicia powder and extracts of jengkol leaves. Ethanol extract jengkol leaves was made in several concentrations, namely 20%, 25%, and 30%, positive control using Tetracycline HCl, and negative control using 1% DMSO. There were several tests carried out on jengkol leaves in addition to phytochemical screening, namely examination of simplicia characteristic including macroscopic examination, microscopic examination, examination of water content, examination of water-soluble extract levels, examination of ethanol-soluble extracts, examination of total ash content, and also an examination of acid-insoluble ash levels and antibacterial activity test of jengkol leaves. The results of phytochemical screening showed that the compound of jengkol leaves (Archidendron pauciflorum Benth.) I.C. Nielsen contained a class of secondary metabolites of alkaloids, flavonoids, tannins, saponins, steroids/triterpenoids, and glycosides. And for the results of the antibacterial activity research also showed that jengkol leaves could be used as antibacterial because it has a strong inhibitory power at a concentration of 20% and the strongest at a concentration of 30% against Staphylococcus epidermidis, namely 15.06 mm and 17.83 mm, while in diameter of growth inhibition zone Propionibacterium acnes was 15.86 mm and 18.1 mm.

Gaharu (Aquilaria malaccensis Lam.) is one of the natural ingredients that can be used as an antioxidant. Antioxidants are compounds that can inhibit free radical reactions in the body. Free radicals have an impact on the pathogenesis of several diseases in humans due to oxidative stress in cells. The purpose of this study was to determine the class of secondary metabolites of agarwood bark and antioxidant activity and to compare the value of IC50 (Inhibitory concentrations) of the methanol extract of agarwood bark with the IC50 of vitamin C in the DPPH method using UV-Vis spectrophotometry. The methanol extract of agarwood bark was macerated using methanol, then determined the content of secondary metabolites of Simplicia. The determination of antioxidant activity was carried out on the methanol extract of agarwood bark with the addition of DPPH at various concentrations. The sample concentrations were 20, 40, 60, 80, and 100 µg/mL.. As a comparison, vitamin C was used with concentrations of 4, 8, 12, 16 and 20 µg/mL.. Then they calculated percent attenuation (% inhibition) and the value of IC50. The results of the screening on the methanol extract of agarwood bark contained chemical compounds such as flavonoids, saponins, and tannins. The determination of antioxidant activity was carried out using a UV-Vis spectrophotometer with the DDPH method. The results were obtained from the methanol extract of the bark of agarwood, which has antioxidant activity in the strong category with an IC50 value of 94.59 µg/mL.and vitamin C in the very strong category with an IC50 value of 22,11 µg/mL.

Chitosan is a modification of chitin compounds that are widely found in the outer skin of crustacean animals such as shrimp and crabs. This research includes isolation of chitin and chitosan: deproteination, demineralization, depigmentation and deacetylation namely transformation of chitin into chitosan, characterization of chitosan, FTIR, and chitosan toxicity test with five concentrations of test solution, namely 100 g/ml, 250 g/ml, 500 g/ml, 750 g/ml and 1000 g/ml using the BSLT method by looking at the number of deaths of Artemia salina L larvae (LC50). The results of tiger prawn shell chitosan (Penaeus monodon) obtained the % degree of deacetylation of 60%. The results of the toxicity test showed that chitosan was not toxic to Artemia salina Leach, indicated by the LC50 value > 1000µg/ml. chitosan windu 4994.16 g/ml, chitosan is not toxic

Curry leaf (Murraya koenigii (L) Spreng) is one of the plants known to have antibacterial compounds. Curry leaves are also known as temurui leaves and are useful as a natural food flavoring. Curry leaves contain flavonoid compounds, alkaloids, calcium, zinc, riboflavin, folic acid. This study aimed to analyze the bioautography and antibacterial activity of ethanol extract of curry leaves against Propionibacterium acnes bacteria. The research method was carried out experimentally. Curry leaf simplicia extract was made with 96% ethanol as solvent. Curry leaf ethanol extract was made in various concentrations, namely 30%, 40% and 50%. The positive control used was Tetracycline HCl and the negative control was DMSO. The tests carried out on curry leaf simplicia included phytochemical screening, macroscopic examination, microscopic examination, water content examination, examination of water soluble extract content, examination of ethanol soluble extract content, examination of ash content and examination of acid insoluble ash content, bioautographic analysis he results of phytochemical screening showed that curry leaves contain secondary metabolites, namely flavonoids, alkaloids, tannins, saponins, steroids/triterpenoids, and glycosides. The results of the antibacterial activity showed that curry leaves could be used as antibacterial because they had strong inhibition at concentrations of 30%, 40% and 50%, namely 10.3 mm, 11.7 mm and 13.6 mm against P. acnes bacteria. The results of bioatuography showed that the Rf value in the clear zone was 0.17 with a ratio of chloroform:n-Hexane (8:2) on the chromatogram spots by spraying 10% FeCl3 positive for flavonoid compounds which were marked in black.