## 4 Discussion
The tensile strength effect on MEL-A treatment had a 22.00% increase and on MEL-B there was a 19.40% increase [36]. Tannins are influential chemical components for emblica extract to coat hair. In this study, 9% EXS [37] treated VH caused tensile strength of 1.29 times and extensibility of 1.63 times more than DI water treated VH. This is consistent with previous studies on the effect of eucalyptus ash on hair, which caused tensile strength to increase by 1.17 times and extensibility by 1.38 times. The tannin in the ash, which is bonded (s-bond) with iron (Fe), made hair stronger and darker [38]. The result of tannin testing is 1.25 g tannin/1000 g emblica extract solution, or 12.0 mg tannin/1 g dried emblica weight which is calculated according to 960 mL emblica extract solution was obtained from 100 g dried emblica. Compare with the tannin from the previous studies, \"Acute and chronic oral toxicity of standardized water extract from the fruit of Phylanthus emblica Linn.\" [39], the tannin content of Amla (_Phylanthus emblica_) fruit was 24.32% _w/w_ or 41.32 mg tannin/1 g dried emblica weight, which is higher than tannin in our study. The higher tannin content may be due to two times the extraction process of emblica (boil for one hour two times compared to boil for one hour one time in our experiment). The total iron was 6.01 mg iron/1000 g emblica extract solution or 0.0576 mg iron/1 g dried emblica. Another study of the iron content from the nutritional value of _Phylanthus emblica_ fruit, \"Indian gooseberry (_Emblica officinalis_): Complete pharmacognosy review\" [40] found that the total iron was 0.0150 mg iron/1 g dried emblica, which is lower than in our study. Another consistent study involves tannic acid, gallic acid, and iron bonded with protein [41], and they were all found in emblica [37; 42]. The study was conducted on the chemical bond in dyed hair [42]. The ingredients used in their formulation included tannic acid, gallic acid, and Fe\({}^{2+}\) (D-gluconate). The formulation is oxidized upon exposure to air and coats hair firmly as blackish tannin nano molecule, as shown in Figure 8. Among the numerous emblica chemical component studies, there are pieces of evidence that emblica extract has a lot of phytochemical compounds, such as gallic acid, tannic acid, iron (Fe), ascorbic acid, ellagitannin, ellagic acid along with flavonoids and kaempfer [43; 44]. Emblica extract solution could be able to coat hair like a chemical bond in hair dyeing. The SEM images selection method is consistent with a previous study of the comparison of hair shaft damage after chemical treatment in Asian, White European, and African hair [28]. The bleaching agent concentration and bleaching time were the major cause of hair damage. As the manufacturing instruction, 12% of Hydrogen peroxide for 1 h causes the cuticle lifted and damaged on bleached hair more than previous studies on 6% of Hydrogen peroxide for 0.5 h. After treated with polyquaternium 7(r) solution, the SEM images showed a roughness caused by the solution on the hair surface which similar to the SEM in this study that EXS were coated on the hair surface. [45]. Comparing the breaking patterns of cross-sectional images of DI water treated hair in Figure 9 (left column) (m, o, q) and 9% EXS treated hair in Figure 9 (right column) (n, p, r) indicates that 9% EXS improved the condition of hair and made it more rigid and harder to break compared with DI water. This experiment is consistent with a previous study on the breaking pattern of hair. There usually are four types of hair fracture patterns, as shown in Figure 9. Fibrillation and splitting tend to occur more in hair in poor condition than smooth and step patterns [46]. Figure 8: The air oxidation of soluble ferrous during hair dyeing and the possible binding of tannic acid, gallic acid, and ferrous. This image was modified with permission from [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON], Gall Ink Revisited: Natural Formulation for Black Hair-Dyeing; published by Cosmetics, 2019 [41].