Introduction
Algae have long been valued for their nutritional benefits, serving as both food and animal feed since ancient times. Primary metabolites such as carbohydrates, proteins, amino acids, and chlorophyll are vital for cellular growth and development. Due to their rich protein, vitamin, and mineral content, algae are considered essential in the food and fodder industries.
Medicinal use of algae dates back to ancient times but gained modern attention only after the 1950s. Algae have demonstrated a range of pharmacological properties, including antibacterial, antiviral, anticancer, antioxidant, anticoagulant, anti-inflammatory, and cardioprotective activities. Traditional medicine, which heavily relies on plant-derived extracts, often benefits from secondary metabolites, known as phytochemicals. These include alkaloids, flavonoids, saponins, tannins, steroids, glycosides, lignin, and phenolic compounds, many of which have antioxidant and antimicrobial effects.
As antibiotic resistance grows, plant-derived compounds offer a safer, more sustainable alternative. Phytochemical screening thus plays a critical role in identifying bioactive substances with therapeutic potential.
Materials and Methods
Collection and Identification
Hydrodictyon reticulatum was collected from the Himalayan region, India—a region located within the the Himalayan hill range, renowned for its biodiversity and medicinal flora. The algae were studied in both live and preserved forms for taxonomic identification. Observations, sketches, and photographs were recorded, and identification was confirmed using taxonomic keys by Nilu Halder (2015).
Biochemical Analysis
Fresh algal material was thoroughly washed and used for quantitative analysis of primary metabolites:
- Carbohydrates – Anthrone Method
- Proteins – Lowry’s Method
- Chlorophyll – Acetone Extraction
- Amino Acids – Ninhydrin Test
- Phenols – Folin-Ciocalteu Method
Preliminary Phytochemical Screening
The dried algal powder was extracted using aqueous, alcoholic, and methanolic solvents and analyzed for phytochemical content following Harborne’s method (1984). Tested compounds included alkaloids, flavonoids, phenolic compounds, steroids, saponins, tannins, anthocyanins, lignin, and glycosides.
Results and Discussion
Morphological Observations
Hydrodictyon reticulatum forms large, macroscopic, net-like colonies that float freely on the water surface. Mature cells can reach up to 50 cm in length and 15 mm in diameter, forming pentagonal, tetragonal, or hexagonal meshes. Young colonies develop within the parent colony, with cylindrical cells containing 2–3 pyrenoids (3.5 mm long, 230 µm wide).
Location: Himalayan region, India
Biochemical Estimation
| Biochemical Component | Content (mg) |
|---|---|
| Carbohydrates | 11.60 ± 0.60 |
| Proteins | 27.67 ± 0.58 |
| Chlorophyll | 0.39 ± 0.01 |
| Amino Acids | 11.00 ± 0.58 |
| Phenols | 15.67 ± 0.24 |
The high protein content underscores the alga’s value as a dietary supplement. Similar phenolic content has been observed in other algal species and is associated with antioxidant and antimicrobial activity. Chlorophyll is also known for its antioxidant and protective effects.
Phytochemical Screening
The following table summarizes phytochemical presence across solvent extracts:
| Compound | Aqueous | Alcohol | Methanol |
|---|---|---|---|
| Alkaloids | ++ | ++ | ++ |
| Flavonoids | ++ | + | + |
| Phenolic Compounds | ++ | ++ | – |
| Steroids | – | + | + |
| Saponins | – | – | – |
| Tannins | ++ | + | + |
| Anthocyanins | – | – | – |
| Lignin | ++ | ++ | ++ |
| Glycosides | ++ | + | ++ |
(Note: “++” = Strong Presence, “+” = Moderate Presence, “–” = Absent)
The presence of diverse phytochemicals indicates significant therapeutic potential. Alkaloids, tannins, and phenolic compounds exhibit known antifungal and antibacterial properties, reinforcing the alga’s suitability for pharmaceutical development.
Conclusion
The freshwater alga Hydrodictyon reticulatum demonstrates rich biochemical and phytochemical diversity. Its high protein and phenolic content make it a promising candidate for use in nutraceuticals and pharmaceuticals. Identified secondary metabolites—such as alkaloids, lignin, glycosides, and flavonoids—are known for their therapeutic and antimicrobial properties, underscoring the potential of this species in combating bacterial infections.
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