The Combination of Turmeric (Curcuma domestica) Rhizome Extract and Collagen in A Serum Formulation as an Antioxidant

A free radical is a relatively unstable molecule with an atom in its outer orbit having one or more unpaired electrons. The molecule that loses the pair becomes unstable and radical. Therefore, this molecule always tries to find its electron pair by seizing electrons from other molecules1,2. Free radicals can damage collagen and elastin, which are a protein that keeps skin moisturized, smooth, flexible, and elastic. Excessive free radical levels trigger various degenerative diseases and conditions in the skin, such as premature aging, wrinkles, erythema, skin cancer, and others3,4. Aging is a process that is a certainty, but premature aging is something that is not expected. The skin's premature aging is characterized by thinning of the skin, dry skin, wrinkles, and uneven coloration5. One of the causes of premature aging is free radical6. One of the ways used to prevent premature aging is to use cosmetics that contain antioxidants. These antioxidants can inhibit the development of oxidation reactions by binding to free radicals and highly reactive molecules to inhibit cell damage7. One of the cosmetic dosage forms that have developed lately to prevent premature aging is serum. The serum has the advantage of having a high concentration of active ingredients so that the skin more quickly absorbs the effect, can provide a more comfortable effect, and is easier to spread on the surface of the skin because the viscosity is not too high8. Research on antioxidant activity from medicinal plants in serum form has been carried out, including by Mardhiani The Combination of Turmeric (Curcuma domestica) Rhizome Extract and Collagen in A Serum Formulation as an Antioxidant


INTRODUCTION
A free radical is a relatively unstable molecule with an atom in its outer orbit having one or more unpaired electrons. The molecule that loses the pair becomes unstable and radical. Therefore, this molecule always tries to find its electron pair by seizing electrons from other molecules 1,2 . Free radicals can damage collagen and elastin, which are a protein that keeps skin moisturized, smooth, flexible, and elastic. Excessive free radical levels trigger various degenerative diseases and conditions in the skin, such as premature aging, wrinkles, erythema, skin cancer, and others 3,4 .
Aging is a process that is a certainty, but premature aging is something that is not expected. The skin's premature aging is characterized by thinning skin, dry skin, wrinkles, and uneven coloration 5 . One of the causes of premature aging is free radical 6 . One of the ways used to prevent premature aging is to use cosmetics that contain antioxidants. These antioxidants can inhibit the development of oxidation reactions by binding to free radicals and highly reactive molecules to inhibit cell damage 7 .
One of the cosmetic dosage forms that have developed lately to prevent premature aging is serum. The serum has the advantage of having a high concentration of active ingredients so that the skin more quickly absorbs the effect, can provide a more relaxing effect, and is easier to spread on the surface of the skin because the viscosity is not too high 8 .
Research on antioxidant activity from medicinal plants in serum form has been carried out, including by Mardhiani Turmeric (Curcuma domestica) has nutritious compounds called curcuminoids, which can be used as antioxidants. As an antioxidant, C. domestica extract can be used to ward off free radicals that damage collagen and elastin, a protein that keeps skin moist. This study aimed to determine the antioxidant activity of serum combined with collagen's addition using the DPPH method. The DPPH was made at a concentration of 80 μg/mL, and the absorption was read at a wavelength of 520 nm using a microplate rider. The study was conducted by making six formulations: F0, F1, F2, F3, F4, and F5 obtained the results of serum made from C. domestica extract that could inhibit free radicals and meet the physical evaluation test requirements of serum. Furthermore, the formula was made using only one active ingredient and only collagen to determine the extract or collagen's antioxidant activity. The results obtained indicate that collagen had a supporting role in adding antioxidant activity apart from its extract. The highest % inhibition value at F5 with 90.526% could ward off free radicals. by testing the formulation and stability of the serum from green coffee (Coffea canephora var. Robusta) extract as an antioxidant where the results showed an IC50 value of 68.89 µg/mL, which is classified as a strong antioxidant 9 .
Another plant whose antioxidant activity has been studied is turmeric (Curcuma domestica). Curcuma domestica is a type of spice with nutritious compounds called curcuminoids consisting of curcumin, desmethoxycurcumin, and bisdemethoxycurcumin, which have various important pharmacological activity such as antioxidants 10 . Naturally, at least 1% of the collagen in the human body is lost every year, and at the age of 40, humans do not produce collagen anymore, so the loss of collagen reaches 35-40%. Therefore, collagen from outside the body is needed, which has an anti-aging activity to prevent aging from occurring faster 14 . Collagen has a vital role in the food, biomedical, pharmaceutical, and cosmetic industries; therefore, collagen is needed for the skin.

Materials
The materials used were C. domestica rhizome obtained in

Extraction
Curcuma domestica rhizome was blanched by boiling at 100°C for five minutes with a medium of 0.05% citric acid solution. Each treatment sample was subjected to an extraction process of 200 g of macerated samples for 72 hours using 96% ethanol solvent and then sonicated using an ultrasonic bath. The solvent of macerate was collected, and it was evaporated using a rotary evaporator until a thick extract was obtained.

Serum formulation
The serum made was based on the results of research by The serum formulation in this study was presented in Table I. Then, a main standard solution of the sample was made with a 1000 μg/mL concentration. Determination of the serum's antioxidant activity was carried out using a microplate reader with the DPPH method at a wavelength of 520 nm. The mixture was incubated in a dark place for 30 minutes and then measured its absorbance at a wavelength of 520 nm using 80 μg/mL DPPH 80 μg/mL, while for the blank used 50 mL methanol absolute 20 .

Data analysis
The absorbance measurements using a microplate reader were used to calculate the percentage of DPPH free radical reduction. The percentage of DPPH free radical reduction was calculated using the following equation:   The finished serum formulation was followed by a physical evaluation test of the preparation. The color and smell test obtained results following Viscosity testing aims to determine the viscosity value of a substance. The higher the viscosity value, the higher the substance's viscosity level 28 . Also, viscosity is related to the ability of a liquid to flow. Viscosity is inversely proportional to dispersibility, in which the higher the viscosity, the lower the dispersibility.
Viscosity also determines the length of the skin's adhesion supply so that the supply can adhere well 29 . In this study, the lowest viscosity obtained at F0 (base) was 30860 cP; collagen's addition increased the preparation's viscosity, which was 34250 cP. The formula containing a combination of collagen and ethanol extract of C.
domestica rhizome had decreased viscosity value, increasing the dispersibility of the preparation. In the irritation test on ten panelists, there were no allergic reactions such as redness, itching, heat, and swelling; it could be seen in Table III.   Table III. Irritation test results  Table IV.