In vitro sunscreen activity of Methanolic root extract of a Sri Lankan grass Heteropogon contortus


W. D. Ratnasooriya1, R. N. Pathirana1, R. N. N. Gamage1*, K. B. Hasanthi1, S. K. Hettihewa2

1Department of Basic Sciences, Faculty of Allied Health Sciences, General Sir John Kotelawala Defence University, Werahera, Sri Lanka.

2Department of Pharmacy, Faculty of Medicine, University of Ruhuna, Karapitiya, Sri Lanka.

*Corresponding Author E-mail:



Although a variety of synthetic sunscreen formulations are available in the market, there is an unprecedental and imperative demand for safe non-comedogenic cheap and efficacious plant based topical sun screens. In this context, the present study was launched to evaluate the sunscreen potential of roots of Sri Lankan grass, Heteropogon contortus (Family: Poaceae) in vitro using a well established UV spectroscopic technique and Mansur  equation. Sun Protection Factor (SPF) was determined (which is an index of sun protective activity) using methanolic extracts (concentration tested 0.05, 0.1 and 0.2 mg/mL) of the roots. Methanol soluble fraction of Dermatone® (concentration tested 0.05, 0.1 and 0.2 mg/mL), a well-known sunscreen cream, was used as the reference agent. The results showed, for the first time, that the root extract exhibited marked sun protection activity: SPF values 12.85 ± 0.87 (mean ± SEM), 12.80 ± 0.13 and 13.02 ± 0.03 respectively for 0.05, 0.1 and 0.2 mg/mL concentrations. However, this effect was not dose-dependent. Corresponding SPF values of Dermatone® were 8.21 ± 0.01, 14.00 ± 0.05 and 27.32 ± 0.12 respectively. This effect was dose-dependent. Phytochemical analysis revealed the presence of flavonoids, phenols, alkaloids, carbohydrates and proteins (based on the phytochemical tests performed). It is concluded that sun protective activity of root extract of H. contortus is mediated primarily by flavonoids and phenols via their antioxidant activity. Also, strong possibility exists to develop safe, cheap, efficacious, user friendly herbal sunscreen from roots of H. contortus.


KEYWORDS: Heteropogon contortus, Sunscreen, Sun Protection Factor, Photoprotection, Antioxidant.



Dermatologists now strongly recommend to apply a topical sunscreen formulation (which absorb, reflect or scatter suns radiation) with a sun protective factor (SPF) value of 15 (threshold value) or greater, preferably year round, to protect the skin and hair against harmful UV rays, especially, UV B rays1,2.


In fact, sunscreen application began in early 20th century3. Currently, there are several sunscreen formulations in the form of creams, oils, gels, ointments, lotions, balms, waxes or butters1,4,5,6. Some of these sunscreens are synthetic and others are natural and herbal1,2,4,6,7. Synthetic sunscreens are generally fast acting, efficacious and provide broad spectrum UV protection1,2,4,7,9,10. However, these are relatively expensive and often induce undesirable side effects, such as contact and/or irritant dermatitis, hypersensitivity, allergies, whitening of skin, vitamin D deficiencies and even skin cancers7,8,9. Moreover, some of these are not user friendly because of their opaque quality, occlusiveness, comedogenicity and tendency to stain cloths1,7,8,9. Yet, an another point of particular concern is that it is claimed that mothers with high blood levels of certain synthetic sunscreen ingredients are more likely to give birth to underweight babies if applied during pregnancy period11. Conversely, herbal sunscreens are claimed to be ecofriendly, safe, efficacious, relatively cheap, noncomedogenic and devoid of undesirable side effects4,5,9,10,11. Accordingly, at present, there is an unprecedental and imperative need to develop novel sunscreens from herbal sources. In this context, we have initiated programme of research to investigate in vitro sunscreen activity in terms of sun protection factor (SPF) of Sri Lankan herbs. As of now, we have evaluated the sun protection activity of orthodox black tea made from leaves of Camellia sinensis12 from salt marshy plants, Suaeda monoica, Suaeda maritima, Halosarcica indica13 and Salicornia brachiata14 leaves of seashore plants. Ipomoea Pes-capprae15, pericarp of Gracinia mangostana16, leaves of Flueggea leucopyrus17 and leaves of Codiaeum veriegatum and its two varieties18.


In this study, we report, for the first time, in vitro sun protective activity of roots of Heteropogon contortus (Eathana in Sinhala and Arukkam-pillu in Tamil), a member of Family Poaceae by assessing the SPF value using UV spectroscopic technique and Mansur equation2,8,12,19.


H. contortus is a perennial grass which grows in Sri Lanka, India, Africa, Southern Asia, Northern Australia and parts of Oceania20,21. The grass has become a naturalised weed in tropical and subtropical regions in Asia. The plant is 0.5 to 1.5 m tall. Leaves and sheaths are green to grey-green in colour. Leaf blades are linear 3-30 cm long, 2-8 mm wide, abruptly narrowed at the tip. Basal sheaths are laterally compressed20,21.


Ethnomedically, H. contortus roots are claimed to treat eye diseases, vomiting, fever, dysentery, epilepsy, swelling, asthma, bronchial diseases, jaundice, phyelitis, gnorrhoea, strangury, wounds, ulcers, diarrhoea, eazemas, diabetes mellitus, body heat conditions and cystitis20,21. Roots are also claimed to be diuretic and aphrodisiae21. Experimentally, methanolic extract of all plant is shown to have bronchorelaxent and antiinflammatory activities22.



Collection of the root (H. contortus):

Fresh matured roots of the plant H. contortus were collected from Galle district (6.0535° N; 80.2210° E), Sri Lanka in June, 2017.





Identification of plant material:

The plant material was identified by Dr. Hashendra, Department of Plant Sciences, Faculty of Sciences, University of Colombo, Sri Lanka. A voucher specimen has been deposited at the Department of Basic Sciences, Faculty of Allied Health Sciences, General Sir John Kotelawala Defence University, Werahera, Sri Lanka.


Preparation of methanolic extract of H. contortus:

Matured roots of H. contortus were taken and washed twice in running tap water. Roots were then cut into small pieces and air dried for a week until a constant weight was obtained. The dried roots were powdered using a domestic blender. Powdered roots (16.5 g) were macerated for 7 days in 150 mL of distilled methanol. The resulting brown coloured extract was filtered through a double layer of cotton and then filtered again through a Whatman filter paper (No: 1). The filtrate was evaporated in a water bath set at 700C until dryness (Yield: 13.63%). The brown coloured product was stored in a sealed beaker and kept in a refrigerator (40C) until use.


Phytochemical analysis of H. contortus methanolic extract:

Methanolic root extract of H. contortus was subjected to following phytochemical screening. Qualitative analysis was performed for alkaloids using Meyer’s and Wagner’s tests. Test for phenols was achieved via Libermann’s test and FeCl3 test. Alkaline reagent test was carried out for flavonoids. Additionally, foam test was performed for the analysis of saponins. Molish test and xanthoproteic test were performed for the investigation of carbohydrate and proteins, respectively. Gelatin test was carried out for tannins.


In vitro evaluation of sun protection factor of methanolic extract of H. contortus:

The brown colour solid of H. contortus methonolic extract was dissolved in methanol and solutions of 0.2 mg/mL, 0.1 mg/mL and 0.05 mg/mL were prepared. Similarly, Dermatone® was dissolved in methanol to obtain solutions of 0.2mg/mL, 0.1 mg/mL and 0.05 mg/mL. These solutions were then kept in water bath at 230C for an hour. Absorbance was determined in 1 cm quartz cell for the above-mentioned concentrations for both methanolic extract of H. contortus and Dermatone® using UV-1800 SHIMADZU spectrophotometer. Absorbance was performed in triplicates for the methanolic extract of H. contortus and Dermatone®, from 290 nm to 320 nm, with 5 nm intervals using ethanol as a blank. SPF values were then calculated using the Mansur equation given below2,8,12,19


SPF = CF x EE (λ) x I (λ) x Abs (λ)


Where: EE – Erythemal effect spectrum; I – Solar intensity spectrum; Abs – Absorbance of sunscreen product; CF – Correction factor (=10). The values of EE x I are constant and predetermined.


Statistical analysis:

The results are given as mean ± SEM. Dose dependencies were investigated using Pearsons’s correlation analysis. Significance was set at P<0.05. 



The results of SPF evaluation of methanolic root extract of H. contortus and reference agent, Dermatone® are depicted in Tables 1 and 2. As shown in Table 1, all the concentrations of H. contortus exhibited moderate sun protective activity in terms of SPF values. The highest SPF value (13.02 ± 0.03) was evident with 0.2 mg/mL concentration and the lowest (12.85 ± 0.87) with 0.1 mg/mL concentration. EC50 value for H. contortus was 0.210 mg/mL. However, the sun protective activity of H. contortus extract was not dose dependent (r2 = 0.725; P>0.05). In contrast, the highest dose of Dermatone® exhibited SPF value of 27.32 ± 0.12 displaying a strong sun protective activity. Lowest concentration (0.05 mg/mL) had a SPF value of 8.21 ± 0.01 which was 36.1% lower than SPF value for the lowest dose of extract. However, SPF values of mid and high concentrations of Dermatone® were 8.57% and 52.34% higher than the corresponding concentrations of the extracts. The sun protective activity of Dermatane® was dose-dependent (r2 = 0.99; P<0.05). EC50 value for Dermatone® was 0.11 mg/mL. Phytochemical analysis revealed the presence of flavonoids, phenols, alkaloids, carbohydrates and proteins (see Table 3).


Table 1: SPF values for methanolic extract of H. contortus at 0.05, 0.1 and 0.2 mg/mL concentrations:

Methanolic extract of H. contortus

Concentration  mg/mL)



12.85 ± 0.87


12.80 ± 0.13


13.02 ± 0.03


Table 2: SPF values for Dermatone® at 0.05, 0.1 and 0.2 mg/mL concentrations


Concentration (mg/mL)



8.21 ± 0.01


14.00 ± 0.05


27.32 ± 0.12


Table 3: Phytochemical analysis of methanolic extract of H. contortus:

Chemical class

Test performed





Meyer’s test



Wagner’s test




Libermann’s test



Neutral FeCl3 test




Alkaline reagent test




Foam test




Molish test




Xanthoproteic test




Gelatin test




This study examined the in vitro sunscreen potential (in terms of SPF value) of methanolic root extract of H. contortus (Family: Poaceae), a common weed in Sri Lanka, using a spectroscopic technique and Mansur equation2,8,12,19. This in vitro bioassay is well recognized, widely used, simple, quick, sensitive, reliable, validated, inexpensive technique to evaluate sunscreen activity of both synthetic and herbal products/formulations4,6,8,23. Furthermore, this in vitro assay bypasses the variability and ethical issues encountered with humans and animals as experimental subjects24. It is also noteworthy that the experimental conditions used in this study were similar to those used by several other investigators4,5,6,8,11 and by us13,14,15,16,17,18.


The results convincingly show, for the first time, that the methanolic root extract of H. contortus has moderate sunscreen activity (in terms of SPF value) at very low concentrations: concentrations of 0.05, 0.1 and 0.2 mg/mL had SPF values of 12.85, 12.80 and 13.02, respectively. Corresponding SPF values for Dermatone®, reference agent at 0.05, 0.1 and 0.2 mg/mL were 8.21, 14.00 and 27.32, respectively. This indicates that root extract is less efficacious compared to Dermatone®. Most organizations and dermatologists recommend to apply a topical sunscreen formulation having SPF value 15 or more, preferably, year around to protect the skin and hair against harmful UV B rays1,2. Moreover, SPF values 2-12, 12-30 and > 30 are recognized as having mild, moderate and high sun protective activity7. What is more, a sunscreen with SPF value of 15 is claimed to protect against 93% of harmful UV B rays and no available sunscreen is capable of protecting 100% UV B rays25. These facts suggest that the root extract of H. contortus can be developed as a safe inexpensive and user-friendly topical sunscreen.


It is well-known that UV B rays provoke the production of variety of aggressive free radicals/molecules such as .O2, .OH, HOO. in the skin4,6,9,26. Free radicals are closely linked with UV B induced pathogenesis of skin damages4,6,26. Sun protective activity of herbal products is often attributed to their antioxidant activity; quenching of free radicals19,26,27. Antioxidant activity of herbal sunscreens are usually mediated by flavonoids19,27, tannins19,27 and alkaloids28. The H. contortus root extract contained flavonoids, phenols and alkaloids. Accordingly, it is quite possible that the sunscreen activity of H. contortus root extract is also mediated by synergestic antioxidant activity of flavonoids, phenolics and alkaloids present in it.


It is concluded that the methanolic root extract of Sri Lankan grass, H. contortus possesses moderate sunscreen activity at very low concentrations. This is a novel finding. Possibility exists to develop a cheap, safe and efficacious sunscreen from roots of H. contortus.



The authors declare no conflict of interest.



1.     Facts about sunscreens. Available from: http://www html (accessed November 14, 2017).

2.     Latha MS, Martis J, Shoba V, Shinde RS, Bangera S, Krishnankutty B, Bellary S, Varughese S, Rao P, Kumar BRN. Sunscreen agents: a review. The Journal of Clinical Aesthetic Dermatology. 2013; 6(1): 16-26.

3.     Khazaeli P, Mehrabani M. Screening of sun protective ability of the ethyl acetate extracts of some medicinal plants. Journal of Pharmacy Research. 2008; 7(1): 5-9.

4.     Mishra AK, Mishra A, Chattopadhyay P. Herbal cosmeceuticals for photoprotection from ultraviolet B radiation: a review. Tropical Journal of Pharmacy Research. 2011; 10(3): 351-360.

5.     Keerthana A. Sun protective activity of herbal drugs: a review. Asian Journal of Pharmaceutical Analysis. 2014; 4(1): 45-46.

6.     Roy A, Sahu RK, Matlam M, Deshmukh VK, Dwivedi J, Jha AK. In vitro techniques to assess the proficiency of skin care cosmetic formulations. Pharmacognosy Reviews. 2013; 7(14): 97-106.

7.     Fauci AS, Braunwald E, Kasper DL, Hauser SL, Longo JL, Loscalzo J. Harrison’s Principles of Internal Medicine. McGrow-Hill, New York. 2008; 17th ed: pp. 350-355.

8.     Dutra EA, Oliveira DAGC, Kedor-Hackmann ERM, Santoro MIRM. Determination of sun protection factor (SPF) of sunscreens by ultraviolet spectrophotometry. Brazilian Journal of Pharmaceutical Sciences. 2004; 40(3): 381-385.

9.     Korac RR, Khambholija KM. Potential of herbs in skin protection from ultraviolet radiation. Pharmacognosy Research. 2011; 5(10): 164-173.

10.   Anitha J. Medicinal plants used in skin protection. Asian Journal of Pharmaceutical and Clinical Research. 2012; 5(3): 35-38.

11.   Kulkami SS, Bhalke RD, Pande VV, Kendre PN. Herbal plants in photoprotection and sunscreen activity: an overview. Indo American Journal of Pharmacy Research. 2014; 4(2): 1104-1112.

12.   Ratnasooriya WD, Jayakody JRAC, Rosa SRD, Ratnasooriya CDT. In vitro sun screening activity of Sri Lankan orthodox black tea (Comellia sinensis Linn). World Journal of Pharmaceutical Sciences. 2014; 2(2): 144-146.

13.   Ratnasooriya WD, Pathirana RN, Dissanayake AS, Samanmali BLC, Desman PK. Evaluation of in vitro sunscreen activities of salt marshy plants Suaeda monoica, Suaeda maritima and Halosarcia indica. International Journal of Pharmaceutical Research and Allied Sciences. 2016; 5(2): 15-20.

14.   Ratnasooriya WD, Pathirana RN, Dissanayake AS, Samanmali BLC, Desman PK. In vitro sun screening activity of salt marshy plant Salicornia brachiata. International Journal of Scientific and Research Publications. 2016; 6(7): 235-238.

15.   Ratnasooriya WD, Pathirana RN, Dissanayake AS, Samanmali BLC, Banu RS. Methanolic leaf extract of Ipomoea Pes-caprae possesses in vitro sunscreen activity. Imperial Journal of Interdisciplinary Research. 2017; 3(2): 150-154.

16.   Ratnasooriya WD, Pathirana RN, Gamage RNN, Hasanthi KB, Hettihewa SK. Sunscreen activity of pericarp of fruit of Sri Lankan Garcinia mangostana L. (Mangosteen) in vitro. Imperial Journal of Interdisciplinary Research. 2017; 3(1): 2225-2229.

17.   Perera LS, Ratnasooriya WD, Pathirana RN. Investigation of in vitro sunscreen activity and phytochemical profile of Flueggea leucopyrus (Wild.). International Journal of Scientific and Research Publications. 2017; 7(4): 127-132.

18.   Banu RS, Ratnasooriya WD, Dissanayake AS, Pathirana RN. In vitro sunscreening activity of Codiaeum veriegetum and its two varieties. International Journal of Scientific and Research Publications. 2017; 7(2): 206-210.

19.   Saraf S, Kaur CD. Phytoconstituents as photoreactive novel cosmetic formulations. Pharmacognosy Reviews. 2010; 4(7): 1-11.

20.   Jayaweera DMA. Medicinal Plants (indigenous and Exotic) Used in Ceylon: Part III. National Science Council of Sri Lanka. 1981; pp: 39.

21.   Barberyn Ayurveda Resorts and the University of Ruhuna. Ayurvedic medicinal plants of Sri Lanka. Available from:;s=Family_rname (accessed November 14, 2017).

22.   Ghante MH, Bhusari KP, Duragkar NJ. Bronchorelaxent and anti-inflammatory effect of Heteropogon contortus (L) Beauv methanolic extract. International Journal of Pharmaceutical Technology Research. 2013; 5(1): 99-104.

23.   Suva MA. Evaluation of sun protective factor of Zingiber officinale roscoe extract by ultraviolet spectroscopy method. Journal of Pharmaceutical Sciences Technology. 2014; 3(2): 95-97.

24.   Mbanga L, Mulenga M, Mpiana PT, Bokolo K, Mumbwa M, Mvingu K. Determination of sunprotection factor (SPF) of some body creams and lotions marketed in Kinshasa by ultraviolet spectrometry. International Journal of Advanced Research in Chemical Science. 2014; 1(8): 7-13.

25.   How dose sunscreens work? Available from: (accessed on November 14, 217).

26.   Herrling T, Jang J, Fuchs J. UV generated free radicals (FR) in skin and hair, their formation, action, elimination and prevention: a general view. SOFW Journal. 2007; 133(8): 2-11.

27.   Ebrahimzadeh MA, Enayatifard R, Khalili M, Ghaffarloo M, Saeedi M, Charati JY. Correlation between sun protection factor and antioxidant activity, phenol and flavonoid contents of some medicinal plants. Iranian journal of pharmaceutical research. 2014; 13(3): 1041-1047.

28.   Chung HS, Shin JC. Characterization of antioxidant alkaloids and phenolic acids from anthocyanin-pigmented rice (Oryza sativa cv. Heugjinjubyeo). Food chemistry. 2007; 104(4): 1670-1677.





Received on 08.02.2018       Accepted on 24.03.2018     

© Asian Pharma Press All Right Reserved

Asian J. Pharm. Ana. 2018; 8(2):65-68.

DOI:  10.5958/2231-5675.2018.00012.1