Traditional Uses Vs Scientific Evidence: A Critical Review Of Hibiscus Flower In Herbal Medicine

The use of medicinal plants has been an integral part of traditional healthcare systems across cultures for centuries. Among these, Hibiscus sabdariffa L. (commonly known as hibiscus or roselle) has gained widespread recognition for its diverse ethnomedicinal applications, ranging from the treatment of hypertension and liver disorders to diuretic and digestive aid. In many regions of Asia, Africa, and Latin America, preparations such as infusions, decoctions, and extracts of hibiscus flowers are routinely consumed as both therapeutic agents and functional foods. These traditional practices are largely attributed to the plant’s rich phytochemical composition, including anthocyanins, flavonoids, organic acids, and other phenolic compounds, which are believed to confer significant health benefits. One of the primary reasons for the widespread traditional use of hibiscus lies in its rich phytochemical profile. The plant contains significant amounts of anthocyanins (such as delphinidin-3-sambubioside and cyanidin-3-sambubioside), flavonoids, phenolic acids, and organic acids like hibiscus acid. These compounds are associated with strong antioxidant properties, which form the biochemical basis for many of their purported therapeutic effects. The antioxidant activity is particularly important in combating oxidative stress, a key factor implicated in chronic diseases such as cardiovascular disorders, diabetes, and cancer. [1-8]

Despite its long-standing use, the transition of hibiscus from a folk remedy to evidence-based herbal medicine requires critical scientific evaluation. Over the past few decades, numerous in vitro, in vivo, and clinical studies have attempted to validate its pharmacological properties. Reported biological activities include antioxidant, antihypertensive, hypolipidemic, anti-inflammatory, and antidiabetic effects, suggesting its potential role in managing chronic non-communicable diseases. However, much of the available evidence is heterogeneous, with variations in study designs, dosages, preparation methods, and study populations, making it difficult to draw definitive conclusions about its efficacy and safety. [1-7]

Another important consideration is safety and potential adverse effects. While hibiscus is generally regarded as safe when consumed as a beverage, high doses or concentrated extracts may interact with medications, particularly antihypertensive and antidiabetic drugs. There is also limited data on its long-term safety and effects in vulnerable populations such as pregnant women and individuals with chronic illnesses. This underscores the importance of integrating traditional knowledge with rigorous toxicological and pharmacokinetic studies. [3,6,7]

Additionally, although traditional knowledge often ascribes broad health benefits to hibiscus, scientific evidence remains limited in some areas due to a lack of large-scale clinical trials and an incomplete understanding of its mechanisms. This gap underscores the importance of critically comparing traditional uses with scientifically validated evidence. Doing so is crucial for accurately identifying genuine therapeutic effects and preventing overestimation of benefits based solely on ethnobotanical claims. [1,2,16]

Therefore, this review aims to critically analyse the traditional uses of hibiscus flower in herbal medicine in comparison with contemporary scientific evidence. By evaluating both ethnomedicinal knowledge and modern pharmacological research, the study seeks to provide a balanced perspective on its therapeutic relevance, limitations, and future research directions.

TAXONOMY [10,32]

• Kingdom: Plantae
• Division: Magnoliophyta
• Class: Magnoliopsida
• Order: Malvales
• Family: Malvaceae
• Genus: Hibiscus
• Species: Hibiscus rosa-sinensis L.

SYNONYMS [32,34]

• Hindi: Gudhal, Japa
• Sanskrit: Japa, Japapushpa, Rudrapushpa
• Bengali: Jaba
• Marathi: Jaswand
• Gujarati: Jasud
• Punjabi: Gudhal
• Malay/Indonesian: Bunga Raya
• English: Chinese Hibiscus, China Rose, Shoe Flower
• French: Hibiscus de Chine
• Spanish: Rosa de China

Note

• “Bunga Raya” is the national flower of Malaysia.
• “Gumamela” is widely used in traditional medicine in the Philippines.

CHEMICAL CHARACTERISTICS AND VARIABILITY [32,33,34]

5. Variation Among Cultivars

• Red flowers → high anthocyanins, strong antioxidant activity.
• White/yellow flowers → higher flavonols, lower antioxidant capacity.

5. Glycosylation

• Most flavonoids occur as glycosides
• Enhances:
  • Solubility
  • Stability
  • Bioavailability

5. Structure–Activity Relationship

• Antioxidant activity increases with:
  • Hydroxyl group substitution
  • Conjugation in flavonoid structure

BIOLOGICAL SIGNIFICANCES OF PHYTOCHEMICALS

The phytochemicals present in hibiscus flowers contribute to: [10,11,13,35]

• Antioxidant activity
• Anti-inflammatory effects
• Anticancer potential
• Antimicrobial activity
• Cardioprotective effects

These properties are primarily due to flavonoids and phenolic compounds. The flowers of Hibiscus rosa-sinensis are chemically rich, with flavonoids (especially anthocyanins and flavonols) as the major constituents, along with phenolics, tannins, alkaloids, and saponins. Their phytochemical diversity underlies their medicinal, nutritional, and ornamental importance, as well as their high antioxidant potential.

TRADITIONAL USES IN HERBAL MEDICINES [14,15,18,25]

Hibiscus rosa-sinensis L. (Malvaceae) is widely used in traditional medicine systems, including Ayurveda, Traditional Chinese Medicine (TCM), and folk medicine. Different parts—especially the flowers and leaves—are used as decoctions, pastes, infusions, and extracts to treat various ailments.

Major Traditional Uses

• Reproductive and Gynecological Uses

• Used as an emmenagogue to regulate menstrual cycles.
• Employed in menstrual disorders and dysmenorrhea.
• Traditionally used as an antifertility and contraceptive agent.
• Used to stimulate labor during childbirth.

• Reported in China, India, Bangladesh, and the Pacific regions.

• Antidiabetic and Cardiovascular Uses

• Used in folk medicine for diabetes mellitus management.
• Helps in hypertension and heart disorders.
• Exhibits cardioprotective effects.

• Widely documented in ethnomedicinal practices.

• Anti-inflammatory and Analgesic Uses

• Flower paste applied to reduce inflammation and pain.
• Used in fever and headache treatments.
• Exhibits anti-pyretic (fever-reducing) activity.

• Respiratory Disorders

• Decoctions used to treat:
  • Cough and bronchitis
  • Influenza and cold

• Used traditionally in Asia and the Pacific Islands.

• Gastrointestinal Disorders

• Used for:
  • Diarrhea and dysentery
  • Gastric ulcers
• Leaf extracts used as antidiarrheal agents.

• Wound Healing and Skin Diseases

• Applied topically for:
  • Wounds and cuts
  • Skin infections and inflammation
• Acts as a cooling and soothing agent

• Hair Care and Cosmetic Uses

• Widely used in Ayurveda for:
  • Hair growth promotion
  • Prevention of hair loss and dandruff.
• Flowers used in herbal oils and hair tonics.

• Antimicrobial and Anti-infective Uses

• Used traditionally to treat:
  • Bacterial and fungal infections.
  • Sexually transmitted diseases (e.g., gonorrhea).

• Kidney and Urinary Disorders

• Used in traditional medicine for:
  • Kidney disorders
  • Diuretic effects

• Aphrodisiac and General Tonic

• Considered an aphrodisiac in some cultures.
• Used as a general health tonic to improve vitality.

REGIONAL ETHANOMEDICINAL USES

Asia

• India: Used in Ayurveda for hair care, menstrual disorders, and wound healing.
• China: Used to regulate menstruation and reduce pain.

Pacific Islands

• Used for:
  • Childbirth support
  • Respiratory ailments

Africa and South America

• Used for:
  • Fever, infections, and reproductive health

MODES OF PREPARATION

Traditional formulations include:

• Decoctions (boiled extracts)
• Infusions (tea-like preparations)
• Pastes (topical application)
• Oils (especially for hair treatment)

PHARMACOLOGICAL ACTIVITIES (SCIENTIFIC EVIDENCE) [20,22,24,28,31]

Hibiscus rosa-sinensis exhibits a wide range of pharmacological activities due to its rich phytochemical profile (flavonoids, anthocyanins, phenolics, saponins). These compounds modulate oxidative stress, inflammation, and metabolic pathways, leading to multiple therapeutic effects.

Major Pharmacological Activities

• Antioxidant Activity

• Strong antioxidant activity demonstrated through:
  • DPPH radical scavenging assay.
  • Lipid peroxidation inhibition.
• Methanolic extracts showed up to 75% radical scavenging activity.

Mechanism

• Scavenging reactive oxygen species (ROS).
• Increasing endogenous antioxidant enzymes (SOD, GSH).

• Anti-inflammatory Activity

• Flower extracts inhibit pro-inflammatory mediators such as:
  • TNF-α
  • IL-6
  • Cyclooxygenase (COX)

Mechanism

• Suppression of inflammatory signaling pathways.
• Inhibition of cytokine production.

• Antidiabetic Activity

• Extracts reduce:
  • Blood glucose levels
  • Postprandial glucose absorption
• Improve lipid profile (cholesterol, triglycerides)

Mechanism

• Enhancement of insulin sensitivity.
• Inhibition of carbohydrate-metabolizing enzymes.

• Cardioprotective and Antihyperlipidemic Activity

• Reduces:
  • LDL cholesterol
  • Triglycerides
• Improves heart function

Mechanism

• Regulation of lipid metabolism pathways:
  • PPAR-γ
  • Fatty acid synthase

• Antimicrobial Activity

• Exhibits activity against:
  • Gram-positive and Gram-negative bacteria
  • Fungal pathogens

Evidence

• Agar diffusion assays confirmed antibacterial activity of flower extracts.

• Anticancer (Cytotoxic) Activity

• Extracts show cytotoxic effects against:
  • Cancer cell lines
• Induces apoptosis (programmed cell death)

Mechanism

• Modulation of oxidative stress and cell signaling pathways.

• Antifertility Activity

• Demonstrated anti-implantation and anti-ovulatory effects in animal studies.

Mechanism

• Hormonal modulation affecting reproductive cycles.

• Antipyretic and Analgesic Activity

• Reduces fever and pain in experimental models.

Mechanism

• Inhibition of prostaglandin synthesis.

• Antidepressant and Neuroprotective Activity

• Exhibits CNS-modulating effects.
• Improves mood and reduces depressive symptoms.

Mechanism

• Modulation of neurotransmitters and oxidative stress.

• Hepatoprotective and Nephroprotective Activity

• Protects the liver and kidneys against toxin-induced damage.

Mechanism

• Reduction of oxidative stress markers.
• Enhancement of detoxifying enzymes.

• Antiulcer and Gastroprotective Activity

• Protects gastric mucosa.
• Reduces ulcer formation.

Mechanism

• Increased mucus secretion.
• Reduction of gastric acid.

• Wound Healing Activity

• Promotes faster wound closure.
• Enhances tissue regeneration.

Mechanism

• Stimulation of collagen synthesis.
• Anti-inflammatory action.

Summary of Mechanisms

Key pharmacological actions are mediated through:

• Antioxidant defense (ROS scavenging).
• Anti-inflammatory pathways (cytokine inhibition).
• Metabolic regulation (glucose and lipid metabolism).
• Cellular protection (anti-apoptotic and cytoprotective effects).

Hibiscus rosa-sinensis demonstrates broad-spectrum pharmacological activities, including antioxidant, anti-inflammatory, antidiabetic, antimicrobial, and anticancer effects. These activities are strongly supported by in vitro, in vivo, and mechanistic studies, validating their traditional medicinal use and highlighting their potential for drug development. [20,28-31,35]

TRADITIONAL CLAIMS VS SCIENTIFIC VALIDATION (CRITICAL COMPARISON)

DOSAGE FORMS AND FORMULATIONS