Formulation and Evaluation of Antioxidant Rich Herbal Liquid Toner

In recent years, there has been a paradigm shift in consumer preference toward natural and herbal-based skincare products, owing to the growing awareness of the harmful effects of synthetic chemicals on the skin. Among the wide range of cosmetic formulations, facial toners play a crucial role in maintaining skin pH, tightening pores, removing residual impurities, and refreshing the skin [1]. Traditionally, toners were alcohol-based and often led to dryness and irritation, especially for sensitive skin types. This has encouraged formulators and researchers to explore natural, plant-based alternatives with multifunctional benefits, particularly those rich in antioxidants, which are essential for combating oxidative stress and preventing premature skin aging [2,3]. Antioxidants are vital in skincare as they neutralize free radicals unstable molecules generated due to environmental pollution, ultraviolet (UV) radiation, and metabolic processes which contribute to the degradation of skin proteins such as collagen and elastin [4]. Herbal ingredients, due to their phytoconstituent-rich profiles, offer an abundant source of natural antioxidants along with anti-inflammatory, antimicrobial, and skin-soothing properties [5]. Green tea (Camellia sinensis) is one of the most extensively researched medicinal plants known for its polyphenolic compounds, especially catechins like epigallocatechin gallate (EGCG), which exhibit potent antioxidant, anti-inflammatory, and antimicrobial activities. It helps reduce skin inflammation, prevents acne, and protects against UV-induced damage [6]. Lemongrass (Cymbopogon citratus) is a tropical herb traditionally used in aromatherapy and herbal medicine. It is rich in flavonoids, phenolic acids, and essential oils such as citral and limonene [7]. Lemongrass exhibits astringent, antibacterial, and detoxifying effects, making it a beneficial ingredient for toning the skin and controlling oil secretion. Hibiscus (Hibiscus sabdariffa), often referred to as the “Botox plant,” is rich in anthocyanins, organic acids, and vitamin C. It has been demonstrated to promote skin elasticity, improve complexion, and provide a mild exfoliating effect [8,9]. The natural acids in hibiscus help to purify the skin by breaking down dead skin cells and increasing cell turnover. The synergistic combination of green tea, lemongrass, and hibiscus offers a promising herbal formulation with enhanced antioxidant potential, making it suitable for incorporation into a liquid toner [10]. However, the development of such a formulation requires careful consideration of physicochemical parameters, microbial stability, antioxidant efficacy, and consumer acceptability [11]. This research article focuses on the formulation, physicochemical evaluation, and antioxidant activity assessment of an herbal liquid toner prepared using aqueous extracts of green tea, lemongrass, and hibiscus. The study aims to provide a safe, effective, and natural skincare alternative that aligns with the rising demand for herbal cosmetic products.

MATERIAL AND METHODS:

MATERIALS

The ingredients used in the formulation include Green tea extract, Hibiscus extract, Lemon grass extract and Rose water sourced from the local market. And all other chemicals and reagents are used in the study are procured from reputed suppliers.

METHODS

Extraction of an active constituent from crude drug:

Weigh 25 g of powdered plant material and transfer it into a 250 mL beaker. Add 250 mL of distilled water and heat the mixture at a controlled temperature (60–70°C) for 1 hours, ensuring continuous heating without boiling. After heating, allow the extract to cool to room temperature and filter it using Whatman filter paper or muslin cloth to separate the liquid extract from plant residues. Transfer the filtrate to an evaporating dish and gently heat using a water bath or rotary evaporator to concentrate and remove excess solvent until a semi-solid or dry residue is obtained. The concentrated extract is then stored in a sterile container and used for the preparation of an herbal face toner [12].

Preparation of Herbal Liquid Toner:

Take the extract of Green tea, Lemon grass and Hibiscus in a beaker and mix well. Add rose water in above mixture. Then add 1ml of glycerin. Add few drops of vinegar or methyl paraben as a preservative. Makeup the volume with distilled water and mix well [13,14].

Table 1: Formulation of Polyherbal Liquid Toner

Evaluation of Polyherbal Liquid Toner [15-21]:

1. Preliminary Phytochemical Screening was done for alkaloids, glycosides, flavonoids, tannins, carbohydrates, proteins, lipids and essential oils with the help of standard protocol.

2. Organoleptic characteristics: Parameters like Appearance, Color, Odor, Homogeneity, Consistency and Texture were evaluated by visual interpretation.

3. Washability: It was determined by rubbing the little amount of toner on hand which was later washed under the running tap water.

4. Determination of pH: For evaluation, as pH of the toner cannot be directly measured, 10% dilutions were made with distilled water and the pH was determined by using digital pH meter.

5. Rancidity: For evaluation, 10 ml of formulation taken and added to 10 ml of concentrated hydrochloric acid along with 10 ml Phloroglucinol solution. The mixture was shaken well for 1 minute. The material shall be taken to have passed the test if no pink color is developed.

6. Determination of Viscosity: Viscosity of the toner was determined by Ostwald viscometer.

7. Loss on drying: 5 ml of formulated toner was taken in a porcelain dish, allowed to dry in hot air oven at 100 ? for 30 minutes. Two consecutive values after drying at the interval of 30 min were recorded and kept in desiccator for 15 min and LOD was determined.

8. Homogeneity: It is analyzed by visual inspection for the appearance and existing of any clog.

9. Skin irritation: Small amount of the toner was sprayed on left hand dorsal skin and kept for some time; result was found non- irritant on the skin.

10. Stability Study:

The herbal liquid toner was kept for three months at two separate temperatures of 4± 2°C and 30± 2°C, with 65% RH. Compared with the original pH and viscosity, the pH and viscosity of the herbal liquid toner were determined after three months [21].

RESULT AND DISCUSSION:

Table 2: Preliminary Phytochemical Screening

2. Organoleptic characteristics: Parameters like Appearance, Color, Odor, Homogeneity, Consistency and Texture were evaluated by visual interpretation.

Table 3: Determination of Evaluation Parameters of Prepared Antioxidant-Rich Polyherbal Liquid Toner

Appearance, Colour and Odour:

All formulations exhibited a water-like appearance, which is desirable for easy application and quick absorption. The light brown color was attributed to the presence of polyphenols and flavonoids from Green Tea, Lemongrass, and Hibiscus. The characteristic odour was mild and pleasant, making it suitable for consumer acceptance.

Washability:

All formulations demonstrated good washability, making them convenient for daily use without leaving residue on the skin.

pH Analysis:

The pH of the formulations ranged between 5.40 to 5.55, which is within the ideal pH range for skincare products (4.5-6.0). This ensures skin compatibility and prevents irritation. Among all, F3 (pH 5.55) was closest to the natural skin pH, making it the most dermatologically suitable formulation.

Rancidity Test:

No pink colour or signs of rancidity were observed in any formulation, confirming the absence of oxidative degradation and ensuring product stability.

Evaluation of Viscosity

The viscosity of a toner plays a crucial role in determining its spreadability, application, and overall user experience.  F1 (15.2 cP) exhibited low viscosity, resulting in fast spreading on the skin; however, it might feel too watery and could require repeated application. F2 (18.5 cP) demonstrated moderate viscosity, ensuring smooth application without excessive runniness, offering a good balance between spreadability and absorption. F3 (20.3 cP), identified as the optimized batch, had the ideal viscosity, providing a balanced texture suitable for spray and cotton pad application. It ensured even distribution without excessive dripping and felt light and refreshing while maintaining sufficient hydration.

Loss on Drying (LOD):

LOD is an essential parameter that determines the moisture content in the formulation. The values ranged from 0.30% (F2) to 0.65% (F1) and 0.50% (F3) with F3 having the moderate moisture content, which may contribute to better stability and shelf life.

Homogeneity:

By visual examination of the appearance and presence of any lumps, flocculates, or aggregates, the formulations were checked for homogeneity. The homogeneity of prepared all formulations liquid toner has been shown to be uniform and homogeneous consistency, ensuring proper distribution of active ingredients.

Irritation Test:

No irritation was observed for any formulation, indicating the dermal safety of the toner.

Stability Study:

The stability of the formulated herbal liquid toner was evaluated over a period of three months under ICH guidelines at 30?C ± 2?C / 75 ± 5% RH. The formulations were stored in lid-tight containers, and samples were analyzed at 0 months (initial) and 3 months for appearance, pH and viscosity to assess any physicochemical changes.

Table4: Stability Study Results