The Effects of Aloe Vera Gel Addition on the Effectiveness of Sunscreen Lotion

Aloe vera is one of the medicinal plants that are heavily used in the pharmaceutical industry, especially in cosmetics. The aloe plant that is cultivated in Indonesia to supply this industry is Aloe chinensis Baker. This research is to determine the effects of Aloe vera gel extract on the effectiveness of sunscreen lotion. The steps taken included Aloe vera gel extraction, flavonoid absorption test, sun protection factor (SPF) value measurement, pH test, viscosity test, homogeneity test, and organoleptic evaluation. The extract was added to the base sunscreen formulation at five different concentrations. UV-Vis spectrophotometry at 290 – 320 nm was performed on the preparations to determine their SPF values. The highest SPF value of 10.21 was found in the preparation containing 20% Aloe vera gel extract. This value falls within the national industrial standard for sunscreen SPF value range of 2 – 60. The research showed that a higher concentration of Aloe vera gel extract increased the pH, with the most elevated pH at 7.0 for the preparation containing 20% Aloe gel vera extract. This value also falls within the national pH standard for sunscreen of 4.5 – 8.0. The higher concentration of Aloe vera gel extract also increased the dispersive amount of the sunscreen preparation, with the highest value of 5 cm resulting from 20% Aloe vera gel extract addition. This research showed that the increased addition of Aloe vera gel extract resulted in higher SPF value.


Introduction
Indonesia is geographically a tropical country, where it receives a large amount of sun radiation (Wasitaatmadja, 2010). This radiation can be beneficial to health, but also has adverse effects, especially from the ultraviolet (UV) at 290-400 nm (Amilum et al., 2013). The degree of skin damage depends on the frequency and length of skin exposure to the sun rays. Skin natural defense in humans can be overwhelmed by excessive UV radiation from the sun. Therefore, there is a need to reinforce this defense, and one of the methods is the use of sunscreen lotions (Soeratri, 2005).
Aloe vera is one of the medicinal plants that are widely used in the pharmaceutical industry, especially in cosmetics. Studies have shown that Aloe vera produces various biologically active compounds that have pharmacological benefits (Marwati and Hermani, 2006). Those active compounds include aloin, emodin, gum, essential oil, and other substrates . In the cosmetic industry, Aloe vera is used as the main ingredient in sunscreen lotion, facial creams, moisturizers, soaps, makeups, perfume, and other beauty and toiletry products.
Sunscreen lotion is a cosmetic product that is used topically to prevent and reduce the harmful effects of sunrays. For a compound to be considered a screening agent, it must be able to absorb the sunrays at the wavelengths of 2800-3200 0 A. Moreover, to be commercially viable, these compounds must not produce an offensive odor and be transparent (Hamdani, 2011). An effective sunscreen must be able to absorb 85% of UVB (290-320 nm) but pass through UVA (>320 nm) (Suryanto, 2012).
The mechanisms of sunscreen action in providing skin protection, according to Lavi (2013) are: 1. Sunscreen molecules absorb the energy of UV rays, which undergo excitation from the ground state to an excited state.
2. When the excited molecules return to a lower state, they will release lower energy than the energy needed for the excitation.
3. Therefore, the high energy UV will have less energy because of the absorption by the sunscreen chemicals.
4. The lowered UV ray energy will have less or no effect on skin sunburn.
A previous study by Pratiwi and Husni (2017) demonstrated that Aloe vera gel extract could be used in sunscreen lotion.
They further explained that Aloe vera gel extract contains Brady kinase enzyme and acemannan polysaccharide that has been known to provide UV protection.

Materials
The main ingredient in this trial is Aloe vera gel extract that had been obtained from the cleaning and peeling of Aloe vera leaves and followed by water removal. Aloe vera was purchased from farmers around West Java with a type of Aloe vera Chinensis Baker. After complete mixing, Part B was slowly added to Part A to form an emulsion. Aloe vera gel extract was added to the emulsion.
The formula of sunscreen is listed in Table 1 while procedure to prepare the sunscreens is shown in Figure 1.
Note: A = Absorbency (Yuliani, 2010)  The addition of Aloe vera gel extract changed the pH of the sunscreen lotion.
Previous research showed that a higher concentration of Aloe vera gel extract increased the pH of sunscreen preparations . Our results show a significant correlation (R 2 = 0.9412) between the concentrations of Aloe vera gel extract and pH values of sunscreen lotion, as presented in Figure 2.  Table 4.  Figure 3. These characteristics include odor, color, and texture. These evaluations were performed using our senses  and the results are presented in Table 5.  . The members of the testing panel prefer cream with a thicker consistency.

Results of spectrophotometry
The sunscreen preparations were dissolved in a solvent of ethanol: water at 3:1. A Spectrophotometer UV-Vis was used to measure the solutions' absorbancy at a wavelength range of 290-320 nm. The results are presented in Table 6. These absorbency results from Table 6 were used to determine the SPF values using the previously described formula. All preparations yielded SPF values above the national standard for minimal SPF value of 4, as presented in Table 7.