Structural characterization and antifungal activity of Algerian Opuntia ficus-indica polysaccharides: FTIR, GC-MS, colorimetric assays, and bioactivity dataStructural and antifungal data: Sequentially extracted polysaccharides from Algerian Opuntia ficus-indica cladodes (FTIR, GC, colorimetric assays)

This dataset comprises raw and processed Fourier-transform infrared (FTIR) spectra obtained via attenuated total reflectance (ATR) for six polysaccharide fractions extracted from Algerian Opuntia ficus-indica cladodes:

Mucilage 1 & 2 (water-soluble fractions)
Pectin 1 & 2 (hot water/EDTA-extracted)
Hemicellulose (alkali-extracted)
Cellulose (residual fraction)
Crude extract (unfractionated control)

Key Features:
- Spectral Range: 4000–400 cm⁻¹ at 4 cm⁻¹ resolution (32 scans)

- Identified Functional Groups:

O–H stretching (3400 cm⁻¹)
Carboxylate C=O (1750 cm⁻¹, pectins)
β-glycosidic linkages (890 cm⁻¹)

- Correlative Data: Monosaccharide composition (GC) and antifungal activity against Penicillium sp. are linked to spectral peaks.

Potential Applications:

Validation of plant polysaccharide extraction protocols
Structure-activity studies for natural antifungals
Comparative analysis of xerophytic plant adaptations

Technical Details:

Files Included:

FTIR-DRAOU.xlsx spectra (wavenumber vs absorbance)
Instrument: Thermo Scientific FTIR spectrometer (OMNIC™ Software)

Ethics: No human/animal subjects involved.

 This dataset supports the research article "*Structural characterization and antifungal properties of...*" [DOI/Lien manuscrit si disponible]. It contains:  

1. FTIR-ATR Spectra  

  - Raw spectra (4000-400 cm⁻¹) of mucilage (M1-M3), pectins (P1-P2), hemicelluloses, and cellulose fractions.  

  - Key peaks: 1750 cm⁻¹ (C=O), 890 cm⁻¹ (β-glycosidic linkages).  

2. Gas Chromatography (GC)  

  - Monosaccharide composition (% molar) of all fractions.  

  - Includes arabinose, rhamnose, xylose, galacturonic acid quantifications.  

3. Colorimetric Assays  

  - Neutral sugars (Dubois method) and uronic acids (Blumenkrantz method).  

  - Corrected values using Montreuil-Spik equations.  

4. Antifungal Bioassays  

  - *Penicillium* sp. growth inhibition data (dose-response, IC50).  

Methods:  

- Extraction: Sequential water/EDTA/KOH protocol.  

- GC: Shimadzu GC-2030 (DB-5 column, TMS derivatization).  

- FTIR: Nicolet iS50, 4 cm⁻¹ resolution.  

Usage Notes:  

- Negative uronic acid values in cellulose set to 0.  

- Missing data = "ND" (Not Detected).