INTRODUCTION:

Coleus amboinicus (synonyms: Plectranthusamboinicus, Coleus aromaticus), often known as Country borage or Indian borage, is a dicotyledonous plant in the Lamiaceae family. The plant is widely distributed throughout India and is grown in gardens. It is a folklore medicinal plant that is used to cure malaria, hepatopathy, renal and vesical calculi, cough, chronic asthma, hiccough, bronchitis, helminthiasis, colic, convulsions, and epilepsy¹.

Inflammation is the body's reaction to tissue injuries or pathogens, and it eventually leads to the restoration of normal tissue structure and function. Acute inflammation is a temporary good process that occurs in response to infectious pathogens, but chronic inflammation is a long-term negative event that can lead to the development of inflammatory illnesses².

Medication administration to the skin is an effective and targeted therapy for local dermatological issues. This route of medication delivery has risen in popularity since it removes the first-pass effects, gastrointestinal irritation, and metabolic degradation associated with oral administration. Only 25-45 percent of the orally taken dose reaches the blood circulation due to the first pass effect. Gel compositions have been proposed as a topical treatment to overcome these drawbacks. Topical gel formulations are a good choice for drug administration since they are less oily and easy to remove from the skin. They are intended for application to the skin or specific mucous membranes for protection, prevention, or therapy³.

The method for topical distribution is dominated by semi-solid formulations in all of their forms. There have been issues about drug diffusion or release from the vehicle and administration through the skin with traditional topical dose forms such as lotions, creams, ointment, and powder. Because creams and lotions are quickly cleansed from the skin and release the medicine from the base, they often have low bioavailability.

The semisolid state is created by increased viscosity caused by interlacing and the resulting internal friction. A gel can also be made up of twisted matted strands that are often linked together by stronger Vander Waals Forces to generate crystalline and amorphous regions throughout the system. Gels are becoming more popular among semisolid dosage forms due to their ease of administration and improved percutaneous absorption⁴.

MATERIAL AND METHODS:

Extraction:

The leaves of the Coleus amboinicuswere collected from Coimbatore, Tamilnadu, during January 2020. The leaves were authenticated by the Botanical Survey of India, TNAU, Coimbatore, and Tamilnadu, India (Fig.1). The collected Plants have been dried at the shade condition at room temperature for two to three weeks. (Fig.2,3). The dried leaves are taken for the next process of extraction where they are grinded into coarse powders. The powdered leaves have been undergone maceration process.

Fig.1.Coleus amboinicus authentication by the Botanical Survey of India, TNAU, Coimbatore,Tamilnadu, India.

Fig.2 Fresh Leaves of Coleus amboinicus

Fig.3: Dried Leaves of Coleus amboinicus

Ethanolic extract:

In a two separate 1000ml beaker 250g of powdered leaves was been macerated with 500ml of Ethanol for maximum 3-4 days or minimum 48hrs. After maceration the ethanolic extract has being filtered, concentrated and the product has been collected⁵.

Aqueous extract:

In a two separate 1000ml beaker 250g of powdered leaves was been macerated with 500ml of aqueous for maximum 3-4 days or minimum 48hrs. After maceration the aqueous extract is being filtered, concentrated and the product has been collected⁶.

Phyto-chemical screening⁷:

· Alkaloid:

Mayer’s test:

In the extract, 2 N HCl was added, followed by 1 or 2 drops of Mayer's reagent. The presence of alkaloids is indicated by the formation of white turbidity.

· Terpenoids:

Salkowski test:

5ml of strong sulphuric acid was carefully added to 1ml of extract combined with 2ml of chloroform to produce a layer. The presence of Terpenoids was revealed by the reddish brown colouring of the interface.

· Saponins:

Foam test:

In a test tube, 1ml of extract was mixed with a small amount of distilled water. For 20 minutes, the solution was vigorously Shaked and monitored for a steady sustained forth. The presence of saponins is indicated by the formation of foamy lather.

· Flavonoids:

Lead acetate test:

A few drops of lead acetate solution are added to the extract sample. The presence of Flavonoids is shown by the formation of a yellow-colored precipitate.

· Tannins:

Braymer’s test:

The extract is treated with 10% alcoholic FeCl₃. The blue-black or green colour indicates the presence of tannins.

Preparation of gel:

Ethanolic extract was taken for the further process of gel formulation since aqueous extract has less activity components compared to the ethanolic extract and hence ethanolic extract is being used to preparing Anti-inflammatory gel.

Tween-80 and different concentrations of HPMC were dissolved in glycerol for Formulation F1, F2 and F3and stirred well.Similarly, Tween-80 was dissolved in glycerol for Formulation F4, F5 and F6 and stirred well.Carbopol-940is a highly effective rheology modifier that may produce high viscosity and creates clear gels that sparkle or hydro-alcoholic gels and creams. Aqueous phase containing different concentrations of carbopol-940 dissolved in water with continuous stirring and heated for 30min at 150ºC.Mix both the mixtures with continuous stirring.Add Triethanolamine by drop wise with continuous stirring.To all the above Formulations the ethanolic extracted extraction of Coleus amboinicus was being added as mentioned in Table.1 and then they were mixed well. The complete gel had been formed (Fig.4). ^8,9,10.

Table.1 Formulation of Coleus amboinicus gel

Formulation	F1	F2	F3	F4	F5	F6
Ethanolic extract of Coleus amboinicus	0.5 g	1.0g	1.5 g	2.0g	2.5 g	3.0g
Carbopol 940	0.4 g	0.5 g	0.6 g	0.4 g	0.5 g	0.6 g
HPMC	0.12g	0.15g	0.18g	-	-	-
Tween-80	0.1ml	0.1ml	0.1ml	0.1ml	0.1ml	0.1ml
Water	70 ml	70 ml	70 ml	70 ml	70 ml	70 ml
Glycerol	5ml	5ml	5ml	5ml	5ml	5ml
Triethanolamine	2ml	2ml	2ml	2ml	2ml	2ml

Fig.4. Gel prepared using Ethanolic extract of Coleus amboinicus

Evaluation of gel:

Homogeneity:

After the produced gel had been set in the container, it was visually inspected for homogeneity. It was examined for aggregate appearance and presence.

Consistency and greasiness:

The consistency and greasiness of the product were tested by putting it to the skin.

Grittiness:

Microscopically, the formulation was examined for the existence of any particles.

Percentage Yield:

To calculate the percentage yield, the empty container was weighed first, then the gel formulations were added and the container was weighed again. The practical yield is obtained by subtracting the weight of the empty container from the weight of the container holding the gel formulation.

Spreadability:

To determine the Spreadability the gel formulation of 1gm was placed between the horizontal plates (20×20 cm²) after 1 minute. A fixed weight of 125gm was connected to the upper plate¹¹.

pH Measurement:

A digital pH meter was used to determine the pH of the formulation.In 100ml of distilled water 1g of gel was dissolved and kept aside for 2hrs. The standard deviation was calculated after measuring the pH of the formulation in triplicate. To avoid irritation, the gel should be close to the skin's normal pH¹².

Extrudability test:

Extrudability test is based upon determination or a weight required to extrude from the suitable collapsible aluminum tube. The test was performed and the average values were calculated. The Extrudability was then calculated using the following formula¹³.

Weight applied to extrude gel from tube (in gm)

Extrudability = -------------------------------------------------

Area(in cm²)

Viscosity:

The viscosity of the gel was measured with a Brookfield viscometer at 25 degrees Celsius with a viscometer spindle speed of 12 revolutions per minute (Fig.5).

In vitro study of anti-inflammatory activity:

Inhibition of albumin denaturation:

A small volume of extract is obtained and 1 percent aqueous solution of bovine albumin fraction is added. A tiny amount of 1N HCl is used to alter the pH of the reaction mixture. The sample extracts were heated at 51^o C for 20 minutes after being incubated at 37^o C for 20 minutes. The turbidity of the samples was measured at 660nm after they had been cooled¹⁴.

(Abs Control- Abs Sample) *100

Percentage inhibition= ----------------------------------------

Abs Control

RESULTS AND DISCUSSION:

Table 2: Phytochemical screening of Coleus amboinicus gel

S. No	Phytochemical Screened	Standard of Test	Aqueous extract	Ethanolic extract
1	Alkaloids	Mayer’s test	_	+
2	Saponins	Foam test	+	+
3	Terpenoids	Salkowski test	_	+
4	Flavonoids	Lead acetate test	_	+
5	Tannins	Braymer’s test	+	+

+ Presence, - Absence

Table 3:Physical Examinationof Coleus amboinicus gel

Formulation	Homogeneity	Consistency and Greasiness	Grittiness	Nature of Gel
F1	Homogeneous	Good consistency	No Gritty particles	Transparent
F2	Homogeneous	Good consistency	No Gritty particles	Transparent
F3	Homogeneous	Good consistency	No Gritty particles	Translucent
F4	Homogeneous	Good consistency	No Gritty particles	Transparent
F5	Homogeneous	Good consistency	No Gritty particles	Transparent
F6	Homogeneous	Good consistency	No Gritty particles	Translucent

Table.4 Characteristics of Coleus amboinicus gel

Formulation	pH	Viscosity (Cp)	Spreadability	Drug content	Extrudability
F1	6.7	27000	9.7	98.46	+
F2	6.5	29900	9.8	97.28	+++
F3	6.2	31000	10.2	99.56	+++
F4	6.8	28600	9.6	98.83	+
F5	6.4	29000	9.5	97.62	++
F6	6.6	29400	9.8	99.03	+++

Excellent (+++), Good (++), Average (+), Poor (-)

Fig.5. Viscosity profile of Coleus amboinicus Gels

Table 5. In vitro Study of Anti-Inflammatory Activity

S. No	Concentration	Control absorbance	Sample absorbance
1	0.2	0.713	0.315
2	0.4	0.713	0.312
3	0.6	0.713	0.31
4	0.8	0.713	0.308
5	1	0.713	-

DISCUSSION:

The present study involved the extraction of Coleus amboinicus from both distilled water and ethanol. Phytochemical screening was done to optimize the extract suitable for gel formulations. Ethanolic extract showed the presence of phytoconstituents like Alkaloids, Saponins, Terpenoids, Flavonoids and Tannins which was selected for gel formulations. With different concentrations of Carbopol 940 and HPMC as gelling agents, different formulations were prepared. All the formulations were evaluated for Physical Examination, Characteristics and Invitro Study of Anti-Inflammatory Activity. The results were as shown in table 2, 3,4 and 5.

CONCLUSION:

The data showed that the polyherbal gels prepared from the dried methanolic extracts Cassia toraLinn., Cassia alataLinn. and Cynodondactylon (L.) Pers. fgave the significant anti-inflammatory activity The data from the study revealed that gels made from Ethanolic extract of Coleus amboinicus had strong anti-inflammatory effect.Since phytochemical testing revealed the presence of Alkaloids, Saponins, Terpenoids, Flavonoids and Tannins in the ethanolic extracts they might suppress the formation of prostaglandins and bradykinins or antagonize their action and exert its activity.

ACKNOWLEDGEMENTS:

The author is thankful to the Management, Karpagam Academy of Higher Education,Coimbatore, Tamilnadu for providing all the necessary facilities to carry out this research work.

CONFLICTS OF INTEREST:

The author declares that there are no conflicts of interest regarding the publication of this paper.

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Received on 23.01.2022 Modified on 13.07.2022

Research J. Pharm. and Tech 2023; 16(4):1971-1975.

DOI: 10.52711/0974-360X.2023.00323