Ethnopharmacological Review and Laboratory Validation of Indigenous Plants Used in Vascular Disorders

2.1 Ethnobotanical Survey

 

An ethnobotanical survey was conducted in selected tribal and rural regions where traditional medicinal practices are actively used. Information was collected from traditional healers, elderly community members, and local practitioners through semi-structured interviews, questionnaires, and guided field walks. Data recorded included plant names, parts used, preparation methods, dosage, and specific vascular-related uses. Quantitative ethnobotanical indices—Frequency of Citation (FC), Use Value (UV), and Fidelity Level (FL%)—were calculated to identify the most important species.

 

2.2 Plant Collection and Authentication

Plant species cited by the majority of informants were collected from their natural habitats. Samples were authenticated by a qualified taxonomist , and voucher specimens were prepared and deposited in the institutional herbarium for future reference.

 

2.3 Preparation of Plant Extracts

Collected plant materials were washed, shade-dried, and powdered. Ethanolic extracts were prepared using Soxhlet extraction (50 g powder with 70% ethanol for 6–8 hours). Aqueous extracts were prepared by boiling 50 g plant powder in distilled water for 30 minutes. All filtrates were concentrated, dried, weighed, and stored at 4°C. Extraction yield (%) was calculated based on the weight of dried extract obtained.

 

2.4 Preliminary Phytochemical Screening

Qualitative phytochemical tests were carried out to detect major groups including alkaloids, flavonoids, phenolics, tannins, saponins, terpenoids, and glycosides using standard procedures such as Mayer’s test, Dragendorff’s test, ferric chloride test, Shinoda test, and froth test.

 

2.5 Quantitative Estimation of Phenolics and Flavonoids

Total Phenolic Content (TPC) was estimated using the Folin–Ciocalteu method and expressed as mg gallic acid equivalents (GAE)/g extract. Total Flavonoid Content (TFC) was determined using the aluminum chloride method and expressed as mg quercetin equivalents (QE)/g extract.

 

2.6 Antioxidant Activity

 

2.6.1 DPPH Assay

Antioxidant activity was assessed using the DPPH radical scavenging method. Extracts (10–200 µg/mL) were mixed with DPPH solution and incubated in the dark. Absorbance was recorded at 517 nm, and percentage inhibition and IC₅₀ values were calculated.

 

2.6.2 FRAP Assay

Ferric reducing antioxidant power was measured by mixing extracts with FRAP reagent and incubating at 37°C. Absorbance was recorded at 593 nm, and results were expressed as µmol Fe²⁺ equivalents/g extract.

 

2.7 Anti-Inflammatory Activity

Anti-inflammatory potential was evaluated using RAW 264.7 macrophage cells. Cells were treated with plant extracts and stimulated with LPS. Nitric oxide production was measured using Griess reagent at 540 nm, and percentage inhibition was calculated.

 

2.8 Vasorelaxant Activity

Ex vivo vasorelaxant activity was assessed using isolated rat aortic rings. Aortae were excised, cleaned, and mounted in an organ bath containing Krebs–Henseleit solution. Rings were precontracted with phenylephrine, and extracts were added cumulatively. Relaxation responses were recorded using a force transducer, and EC₅₀ values were determined.

 

2.9 Statistical Analysis

All experiments were conducted in triplicate. Data were expressed as mean ± standard deviation (SD). Statistical significance was determined using one-way ANOVA followed by Tukey’s post hoc test, with p < 0.05 considered significant.

The results of the ethnopharmacological survey, phytochemical analysis, antioxidant assays, anti-inflammatory testing, and vasorelaxant studies provide comprehensive evidence supporting the traditional use of selected indigenous plants in vascular disorders. Detailed findings are presented below.

 

3.1 Ethnobotanical Survey Results

A total of 28 medicinal plant species belonging to 24 families were documented as remedies for vascular disorders such as hypertension, chest tightness, varicose veins, and inflammatory swelling. Among these, five species showed superior ethnobotanical indices and were selected for laboratory validation.

 

 

Table 1. Ethnobotanical Importance of Frequently Used Vascular Plants

 

Botanical Name  FC (%)   UV          FL (%)    Part Used               Traditional Preparation

 

Terminalia arjuna               89           0.92        88           Bark       Decoction for hypertension, chest pain

Withania somnifera            76           0.84        81           Roots     Powder with milk for stress-induced BP

Moringa oleifera 72           0.79        78           Leaves   Infusion for blood flow & swelling

Curcuma longa    63           0.74        72           Rhizomes              Paste or decoction for inflammation

Allium sativum     58           0.71        69           Bulbs.     Raw cloves for cholesterol & BP

 

Interpretation:

High FC and UV values confirm strong community reliance on these species for circulatory disorders.

 

3.2 Phytochemical Composition

 

All extracts demonstrated the presence of major secondary metabolites associated with vascular protection.

 

 

Table 2. Qualitative Phytochemical Screening of Selected Plants

 

Phytochemical     T. arjuna               M. oleifera            C. longa                W. somnifera        A. sativum

 

Flavonoids            +++         +++         ++           ++           +

Phenolics               +++         ++           ++           ++           +

Tannins +++         ++           +              +              +

Alkaloids               +              +              -               ++           -

Saponins               ++           +++         +              +              ++

Terpenoids            ++           ++           +++         +              +

 

 

(+ = low, ++ = moderate, +++ = high)

 

Interpretation:

T. arjuna and M. oleifera are phytochemically rich, while C. longa is particularly high in terpenoids (curcuminoids).

 

 

3.3 Total Phenolic Content (TPC) and Total Flavonoid Content (TFC)

 

Table 3. TPC and TFC Values of Plant Extracts

 

Plant       TPC (mg GAE/g)  TFC (mg QE/g)

 

T. arjuna               214.6 ± 3.4            91.2 ± 1.4

M. oleifera            187.9 ± 2.8            98.4 ± 1.6

C. longa                162.3 ± 2.1            84.7 ± 1.1

W. somnifera        143.7 ± 1.9            72.6 ± 1.0

A. sativum             121.5 ± 2.5            57.3 ± 0.9

 

 

 

 

Interpretation:

Higher TPC and TFC indicate robust antioxidant potential, which correlates strongly with vascular protection.

3.4 Antioxidant Activity

 

3.4.1 DPPH Radical Scavenging

 

Table 4. IC50 Values of Extracts in DPPH Assay

 

Plant       IC₅₀ (µg/mL)

 

T. arjuna               34.8 ± 1.1

M. oleifera            41.5 ± 1.3

C. longa                47.2 ± 1.0

W. somnifera        52.6 ± 1.5

A. sativum             59.3 ± 1.8

 

 

Interpretation:

Low IC₅₀ values confirm strong radical scavenging ability, especially in T. arjuna.

3.4.2 FRAP Assay

 

Table 5. FRAP Values of Extracts

 

Plant       FRAP Value (µmol Fe²⁺/g)

 

T. arjuna               1289.4 ± 12.5

M. oleifera            1124.7 ± 10.8

C. longa                986.5 ± 9.7

W. somnifera        874.2 ± 8.9

A. sativum             765.3 ± 7.5

 

 

 

 

Interpretation:

T. arjuna demonstrates the highest ferric-reducing ability, confirming its strong antioxidant profile.

 

3.5 Anti-Inflammatory Activity

Nitric oxide inhibition indicates suppression of inflammation, a key factor in vascular protection.

 

Table 6. NO Inhibition (%) at 200 µg/mL

 

Plant       NO Inhibition (%)

 

C. longa                72.4 ± 2.1%

W. somnifera        68.9 ± 1.8%

T. arjuna               64.3 ± 1.5%

M. oleifera            59.7 ± 1.6%

A. sativum             52.8 ± 1.9%

 

 

Interpretation:

C. longa is most effective due to curcuminoids’ strong anti-inflammatory action.

 

3.6 Vasorelaxant Activity

 

Table 7. Vasorelaxation (%) of Aortic Rings at 200 µg/mL

 

Plant                    % Relaxation

 

A. sativum            78.5 ± 2.4%

T. arjuna               72.1 ± 2.1%

M. oleifera            66.3 ± 1.9%

W. somnifera        58.7 ± 1.6%

C. longa                52.9 ± 1.3%

 

Table 8. EC₅₀ Values of Extracts

 

Plant.                      EC₅₀ (µg/mL)

 

A. sativum             48.6 ± 1.4

T. arjuna               55.3 ± 1.2

M. oleifera            63.1 ± 1.5

 

Interpretation:

Allium sativum shows the strongest vasodilatory action, supporting its use in hypertension.

 

3.7 Correlation Analysis

 

Table 9. Correlation Matrix

 

Parameter Pair                                   Correlation ®

 

TPC vs DPPH                                            0.87

TFC vs DPPH.                                      0.84

Antioxidant vs Vasorelaxation         0.81

FC vs Lab Activity.                             0.79

The present study combined ethnopharmacological documentation with laboratory-based phytochemical and pharmacological analyses to validate the use of selected indigenous plants traditionally employed in the management of vascular disorders. The findings strongly support the therapeutic relevance of Terminalia arjuna, Withania somnifera, Moringa oleifera, Curcuma longa, and Allium sativum, as indicated by both traditional knowledge and experimental outcomes.

 

4.1 Ethnobotanical Significance and Traditional Relevance

The ethnobotanical survey revealed that T. arjuna had the highest Frequency of Citation (89%), Use Value (0.92), and Fidelity Level (88%), confirming its central role in traditional cardiovascular care. Similar observations have been reported in ethnomedicinal studies across India, where T. arjuna bark decoctions are routinely prescribed for hypertension and angina-like symptoms.

 

The high cultural importance of W. somnifera, M. oleifera, and C. longa is consistent with their known role in reducing stress-induced hypertension, enhancing circulatory efficiency, and alleviating vascular inflammation. A. sativum showed moderate, yet significant usage, which aligns with its historical role in improving lipid profile and regulating blood pressure. The strong correlation (r = 0.79) between ethnobotanical indices and laboratory activity further validates indigenous knowledge systems.

 

4.2 Phytochemical Constituents and Their Biological Implications

The qualitative and quantitative phytochemical assessments revealed high levels of phenolics, flavonoids, tannins, and terpenoids across all selected plants. T. arjuna and M. oleifera exhibited the highest Total Phenolic Content (214.6 ± 3.4 mg GAE/g and 187.9 ± 2.8 mg GAE/g, respectively), while M. oleifera showed the highest Total Flavonoid Content (98.4 ± 1.6 mg QE/g). These phytochemicals are well known for enhancing endothelial function, reducing oxidative stress, and preventing vascular degeneration.

 

The identification of such compounds is consistent with previous reports where phenolics and flavonoids are established as major contributors to vasoprotective mechanisms, particularly through free-radical scavenging and nitric oxide–mediated vascular relaxation.

 

4.3 Antioxidant Activity and its Vascular Relevance

 

Interpretation:

High correlation values indicate that traditional medicinal importance aligns strongly with laboratory potency.