This clinical trial investigated herbal syrup's effect on treating patients with mild to moderate acne vulgaris. The results showed a significant decrease in the mean number of comedones, papules, pustules, and nodules and a reduction in ASI after 12 weeks of herbal syrup consumption. However, the results did not sustain after 4 weeks from discontinuing intervention.
There is a wide variety of methods for treatments of acne, such as anti-androgen, hormonal, or anti-seborrheic medicines and medications like retinoids, isotretinoids, azelaic acid, and salicylic acid, but many have some side effects (
9). Herbal medicine has been used since antiquity in different conditions such as cardiovascular diseases, diabetes, hypertension, and cancer (
9,
20). Many patients with acne or other infectious skin diseases use complementary and alternative medicine interventions, particularly medicinal plants (
21). A systematic review by Fisk et al. demonstrated that approximately 23 studies indicated the positive effects of herbal products on acne vulgaris (
22).
Several medicinal plants have demonstrated suppressive effects on the growth of bacteria, fungi, and viruses under ex vivo conditions, and some of them have been proven to have anti-inflammatory and lipid-lowering properties (
23). Thus, herbs can be used along with other therapeutic measures or topical or orally in the case of acne. Traditional Persian medicine recommends some specific medicinal plants, such as plants used in the present study, that can be helpful in combination with conventional medications for the treatment of acne vulgaris (
24).
Plum contains many bioactive compounds such as chlorogenic acids, anthocyanins, flavanols, flavonols, and coumarins with antimicrobial and antioxidant properties (
25), which can alleviate inflammation and skin dryness from acne (
26). In Persian medicine, the plum as cold-tempered food has laxative and moisturizer properties, which help to decrease inflammation and irritation (
26). Plums' antimicrobial, anti-inflammatory, and anti-allergic effects were observed in recent studies (
27).
According to Persian medicine, tamarind contains tannin, carbolic acid, and resin substances with cold-dry nature (
28). A study by Waqas et al. demonstrated skin lightening and sebum reduction properties of tamarind seed extract, which could be useful in acne treatment (
29). One of its important therapeutic properties is detoxification of the body to adjust the temperaments, particularly hot temperaments such as eczema and bile heat. For this reason, regular use of the tamarind extract considerably helps improve dermal diseases such as acne and rashes (
30).
Jujube is a plant with a high medicinal value used traditionally in different conditions such as swollen joints, constipation, diarrhea, burns, and acne (
31). About 79 bioactive compounds in this herb indicate various pharmacological effects of jujube, like anti-inflammatory, antifungal, antiulcer, anti-stress, and sedative properties (
32). Several studies demonstrated a strong association between psychological stress and acne severity (
33,
34). An animal study by Al-Reza and colleagues demonstrated that jujube essential oil could improve the inflammatory level in the skin (
35).
Golden shower (
Cassia fistula) is a popular medicinal plant that has been traditionally used alone or in combination with other herbs in Unani and Ayurvedic medicines for the treatment of different conditions such as liver disorders, diabetes, or skin diseases (
36). It is widely used in dermatological problems, such as pruritus, leucoderma, impetigo, eczema, and ringworm (
37). Due to this plant's antioxidant, anti-inflammatory, antimicrobial, and antifungal activities, traditional Persian medicine recommends it as an effective agent in treating acne. A trial by Khan and collaborators on healthy adult men concluded that
C. fistula extract could improve skin hydration and help rejuvenate skin aging (
38). Another study approved the efficacy and safety of this herb as a purgation therapy for skin diseases (
39). In addition, creams that contain
T. chebula demonstrated beneficial effects on rejuvenating human skin (
40). An experimental study by Swindell et al. indicated that the positive effects of
Terminalia chebula are not limited to the dermal layer and result from a change in the epidermis (
41).
Psychological disorders should be considered when treating acne because they may lead to depression and anxiety (
42). In the current study, there was a significant difference between groups regarding CADI scores at the beginning. This difference became more significant by an increase in score in the placebo group and a decrease in score in the intervention group after 12 weeks of study, but these changes were not significant. Some studies have demonstrated that it's possible that the improvement in acne may be attributed to psychological factors, leading to an overall improvement in one's quality of life (
43,
44).
In the present study, although the number of adverse drug reactions in the intervention group was higher than in the control group, this difference was not significant.
Although this is the first study with a sufficient and appropriate sample size, triple-blinded design, and follow-up after 12 weeks of intervention, there were some limitations in the study. Firstly, no biochemical markers were analyzed during the study, which was due to limited resources. Secondly, a questionnaire was used to measure the number of comedones, papules, pustules, and nodules, as well as the ASI.
To sum up, the findings of the current trial showed that the herbal syrup containing plum, jujube, yellow myrobalan, golden shower, tamarind, and honey could effectively ameliorate inflammatory and non-inflammatory lesions in acne vulgaris. Therefore, this syrup can be considered a complementary medicine compound, but more studies are required to obtain more power and assess the long-term effects of this herbal product.